Pub Date : 2020-08-01DOI: 10.1093/forestry/cpaa030
D. Vaughan, D. Auty, J. Dahlen, A. S. Meador, K. Mackes
Wood removed in Southwestern US forest restoration treatments currently has limited markets and thus low value. One important property of wood in structural products is its stiffness (measured as modulus of elasticity), which is known to vary systematically within trees. Directly measuring wood stiffness is expensive, time consuming and destructive. Therefore, we tested samples of ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) from northern Arizona destructively in bending and also non-destructively using acoustic velocity (AV) methods. In total, we tested multiple pith-to-bark small clear (2.54 × 2.54 × 40.64 cm) samples from up to four heights in 103 trees. We first measured the standing-tree AV of sample trees, then the AV of small clear samples, and finally measured wood stiffness using three point static bending tests. We found that a Michaelis–Menten curve was a good fit to the radial profile of wood stiffness, with a steep increase outward from the pith that approached an asymptote. The AV of small clear samples, coupled with measured volumetric density values, approximated the static modulus of elasticity values with high accuracy (r2 = 0.86). At the stand level, a model predicting standing tree AV from tree morphology fit the data well (r2 = 0.77). Results indicate that southwestern ponderosa pine contains outerwood with relatively high stiffness that could be suitable for structural products. However, when assessed using wood stiffness, the trees take a long time to reach maturity (~50 years) and thus the corewood proportion is large. AV measurements are a good way to assess variability within and among stands and thus could be employed to segregate the resource by expected stiffness values. Segregation could help identify stands not suitable for structural uses and direct them toward more appropriate products.
{"title":"Modelling variation in wood stiffness of Pinus ponderosa using static bending and acoustic measurements","authors":"D. Vaughan, D. Auty, J. Dahlen, A. S. Meador, K. Mackes","doi":"10.1093/forestry/cpaa030","DOIUrl":"https://doi.org/10.1093/forestry/cpaa030","url":null,"abstract":"\u0000 Wood removed in Southwestern US forest restoration treatments currently has limited markets and thus low value. One important property of wood in structural products is its stiffness (measured as modulus of elasticity), which is known to vary systematically within trees. Directly measuring wood stiffness is expensive, time consuming and destructive. Therefore, we tested samples of ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) from northern Arizona destructively in bending and also non-destructively using acoustic velocity (AV) methods. In total, we tested multiple pith-to-bark small clear (2.54 × 2.54 × 40.64 cm) samples from up to four heights in 103 trees. We first measured the standing-tree AV of sample trees, then the AV of small clear samples, and finally measured wood stiffness using three point static bending tests. We found that a Michaelis–Menten curve was a good fit to the radial profile of wood stiffness, with a steep increase outward from the pith that approached an asymptote. The AV of small clear samples, coupled with measured volumetric density values, approximated the static modulus of elasticity values with high accuracy (r2 = 0.86). At the stand level, a model predicting standing tree AV from tree morphology fit the data well (r2 = 0.77). Results indicate that southwestern ponderosa pine contains outerwood with relatively high stiffness that could be suitable for structural products. However, when assessed using wood stiffness, the trees take a long time to reach maturity (~50 years) and thus the corewood proportion is large. AV measurements are a good way to assess variability within and among stands and thus could be employed to segregate the resource by expected stiffness values. Segregation could help identify stands not suitable for structural uses and direct them toward more appropriate products.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"52 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73649595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-30DOI: 10.1093/forestry/cpaa027
V. Stokes, G. Kerr, T. Connolly
There is a strong policy move in Britain to improve forest resilience to climate change by increasing stand structural and species diversity. Although currently little used in Britain, the technique of underplanting allows regeneration and diversification of stands while avoiding some of the disadvantages of clearfelling. Two experiments were examined: (1) the growth and survival of five underplanted conifer species of differing shade tolerance in a shelterwood and (2) compared performance of underplanted and open-grown Douglas-fir seedlings on restocking sites. Underplanted Sitka spruce, Norway spruce, noble fir, European silver fir and Douglas-fir were all able to survive and grow. However increased exposure following overstorey removal resulted in some damage and ‘socketing’, especially to taller seedlings, particularly Douglas-fir. This may be linked to poor root development when growing under an overstorey. Microclimate conditions on some underplanted sites were more sheltered from extreme climatic conditions, and in some cases this improved survival of Douglas-fir seedlings. However, seedling growth rates were reduced compared with those on open sites probably due to lower light levels. Underplanting may help to improve establishment success of some species, particularly in exposed areas. However, the shelter benefits of underplanting must be carefully balanced against the trade-off with lower light, and underplanting is likely to be more successful where low canopy density is maintained.
{"title":"Underplanting is a practical silvicultural method for regenerating and diversifying conifer stands in Britain","authors":"V. Stokes, G. Kerr, T. Connolly","doi":"10.1093/forestry/cpaa027","DOIUrl":"https://doi.org/10.1093/forestry/cpaa027","url":null,"abstract":"\u0000 There is a strong policy move in Britain to improve forest resilience to climate change by increasing stand structural and species diversity. Although currently little used in Britain, the technique of underplanting allows regeneration and diversification of stands while avoiding some of the disadvantages of clearfelling. Two experiments were examined: (1) the growth and survival of five underplanted conifer species of differing shade tolerance in a shelterwood and (2) compared performance of underplanted and open-grown Douglas-fir seedlings on restocking sites. Underplanted Sitka spruce, Norway spruce, noble fir, European silver fir and Douglas-fir were all able to survive and grow. However increased exposure following overstorey removal resulted in some damage and ‘socketing’, especially to taller seedlings, particularly Douglas-fir. This may be linked to poor root development when growing under an overstorey. Microclimate conditions on some underplanted sites were more sheltered from extreme climatic conditions, and in some cases this improved survival of Douglas-fir seedlings. However, seedling growth rates were reduced compared with those on open sites probably due to lower light levels. Underplanting may help to improve establishment success of some species, particularly in exposed areas. However, the shelter benefits of underplanting must be carefully balanced against the trade-off with lower light, and underplanting is likely to be more successful where low canopy density is maintained.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"126 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79060624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-28DOI: 10.1093/forestry/cpaa024
David Montwé, Bryan Elder, P. Socha, J. Wyatt, D. Noshad, N. Feau, R. Hamelin, M. Stoehr, J. Ehlting
Substantial growth losses in Douglas-fir can be the result of Swiss needle cast, a foliar disease caused by the fungus Nothophaeocryptopus gaeumannii. Although the disease is native to western North America, it is expected to become increasingly problematic in regions where climates become warmer in winter and wetter in spring, such as in coastal British Columbia (BC), Canada. Previous research suggests that tolerance to this disease is under partial genetic control. We therefore aim to screen for tolerance and resistance to the disease in the tree breeding population of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) in BC. We evaluated if early screening for resistance or tolerance to this disease is possible. We worked with 32 families grown for 18-years on two full-sibling genetic field trial sites representing different climates. We assessed >900 trees for disease signs and symptoms from 2017 to 2019. Needle retention was assessed in the field. In the laboratory, the proportion of stomata occluded with pseudothecia was measured, deoxyribonucleic acid (DNA) was extracted, and the proportion of fungal DNA in the needles was assessed using quantitative polymerase chain reaction. Strong differences were observed among families for needle retention, stomatal occlusion and fungal load. The milder and wetter site closer to the coast was generally more severely affected. Families showed rank changes between the two sites for all response variables. Higher needle retention was correlated with increased tree volume. No correlation was found between the proportion of stomata occluded with pseudothecia, fungal DNA load and needle retention. These results indicate that a more complex pathology is involved in causing needle loss. We conclude that screening for Swiss needle cast tolerance in the coastal BC Douglas-fir breeding population is possible if needle retention can be assessed and that area-specific deployment strategies may be needed given family rank changes in different environments.
{"title":"Swiss needle cast tolerance in British Columbia’s coastal Douglas-fir breeding population","authors":"David Montwé, Bryan Elder, P. Socha, J. Wyatt, D. Noshad, N. Feau, R. Hamelin, M. Stoehr, J. Ehlting","doi":"10.1093/forestry/cpaa024","DOIUrl":"https://doi.org/10.1093/forestry/cpaa024","url":null,"abstract":"\u0000 Substantial growth losses in Douglas-fir can be the result of Swiss needle cast, a foliar disease caused by the fungus Nothophaeocryptopus gaeumannii. Although the disease is native to western North America, it is expected to become increasingly problematic in regions where climates become warmer in winter and wetter in spring, such as in coastal British Columbia (BC), Canada. Previous research suggests that tolerance to this disease is under partial genetic control. We therefore aim to screen for tolerance and resistance to the disease in the tree breeding population of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) in BC. We evaluated if early screening for resistance or tolerance to this disease is possible. We worked with 32 families grown for 18-years on two full-sibling genetic field trial sites representing different climates. We assessed >900 trees for disease signs and symptoms from 2017 to 2019. Needle retention was assessed in the field. In the laboratory, the proportion of stomata occluded with pseudothecia was measured, deoxyribonucleic acid (DNA) was extracted, and the proportion of fungal DNA in the needles was assessed using quantitative polymerase chain reaction. Strong differences were observed among families for needle retention, stomatal occlusion and fungal load. The milder and wetter site closer to the coast was generally more severely affected. Families showed rank changes between the two sites for all response variables. Higher needle retention was correlated with increased tree volume. No correlation was found between the proportion of stomata occluded with pseudothecia, fungal DNA load and needle retention. These results indicate that a more complex pathology is involved in causing needle loss. We conclude that screening for Swiss needle cast tolerance in the coastal BC Douglas-fir breeding population is possible if needle retention can be assessed and that area-specific deployment strategies may be needed given family rank changes in different environments.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"43 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88532268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-24DOI: 10.1093/forestry/cpaa023
Marine Duperat, B. Gardiner, Jean-Claude Ruel
Widely distributed in Quebec, balsam fir (Abies balsamea (L.) Mill.) is highly vulnerable to wind damage. Recently, there has been a trend in forest management to increase the use of partial cuttings in naturally regenerating stands, leaving the remnant trees at increased risk of wind damage. In order to limit wind damage after partial cuttings, it is therefore important to find silvicultural practices that minimize the risk of wind damage in these fir stands. Our main objective was to find balsam fir-specific values of parameters to integrate into the wind risk model ForestGALES, in order to simulate the impact of different types of commercial thinning on wind damage risk, and to determine which practice potentially minimizes the risk in a naturally regenerated stand. An anemometer placed at canopy height and strain gauges attached to the trunks of balsam firs allowed us to measure the wind-induced bending moments experienced by a sample of balsam fir trees. This enabled the calculation of the turning moment coefficients specific to each of the trees in order to compare them with the ForestGALES model predictions and to adapt the model for balsam fir stands. The model was tested first with only tree diameter and height as input variables to calculate the turning moment coefficient, then with the addition of a competition index, and finally with the addition of crown dimensions. Wind climate parameters for prediction of the probability of damage were calculated using the Wind Atlas Analysis and Application Program airflow model. The model with the highest accuracy was then used to simulate two types of thinning and determine the impact on wind damage risk for each tree in the stand. According to the model’s predictions, thinning from below has a reduced risk of wind damage compared with thinning from above.
广泛分布于魁北克的香脂冷杉(Abies balsamea (L.)))极易受到风的破坏。最近，在森林管理方面有一种趋势，即在自然再生的林分中增加部分采伐的使用，使剩余的树木面临更大的风害风险。因此，为了限制部分插枝后的风害，重要的是要找到将这些冷杉林风害风险降至最低的造林方法。我们的主要目标是找到香脂冷杉特定的参数值，将其整合到风风险模型ForestGALES中，以模拟不同类型的商业间伐对风损害风险的影响，并确定哪种做法可能将自然再生林分的风险降至最低。放置在树冠高度的风速计和连接在香脂冷杉树干上的应变计使我们能够测量香脂冷杉树样本所经历的风致弯度。这样就可以计算出每棵树特有的弯矩系数，以便与ForestGALES模型的预测结果进行比较，并使该模型适用于香脂冷杉林。首先以树径和树高为输入变量计算弯矩系数，然后加入竞争指数，最后加入树冠尺寸。利用Wind Atlas Analysis and Application Program气流模型计算了用于预测损伤概率的风气候参数。然后使用精度最高的模型来模拟两种类型的间伐，并确定对林分中每棵树的风害风险的影响。根据该模型的预测，与从上面变薄相比，从下面变薄的风灾风险更低。
{"title":"Testing an individual tree wind damage risk model in a naturally regenerated balsam fir stand: potential impact of thinning on the level of risk","authors":"Marine Duperat, B. Gardiner, Jean-Claude Ruel","doi":"10.1093/forestry/cpaa023","DOIUrl":"https://doi.org/10.1093/forestry/cpaa023","url":null,"abstract":"\u0000 Widely distributed in Quebec, balsam fir (Abies balsamea (L.) Mill.) is highly vulnerable to wind damage. Recently, there has been a trend in forest management to increase the use of partial cuttings in naturally regenerating stands, leaving the remnant trees at increased risk of wind damage. In order to limit wind damage after partial cuttings, it is therefore important to find silvicultural practices that minimize the risk of wind damage in these fir stands. Our main objective was to find balsam fir-specific values of parameters to integrate into the wind risk model ForestGALES, in order to simulate the impact of different types of commercial thinning on wind damage risk, and to determine which practice potentially minimizes the risk in a naturally regenerated stand. An anemometer placed at canopy height and strain gauges attached to the trunks of balsam firs allowed us to measure the wind-induced bending moments experienced by a sample of balsam fir trees. This enabled the calculation of the turning moment coefficients specific to each of the trees in order to compare them with the ForestGALES model predictions and to adapt the model for balsam fir stands. The model was tested first with only tree diameter and height as input variables to calculate the turning moment coefficient, then with the addition of a competition index, and finally with the addition of crown dimensions. Wind climate parameters for prediction of the probability of damage were calculated using the Wind Atlas Analysis and Application Program airflow model. The model with the highest accuracy was then used to simulate two types of thinning and determine the impact on wind damage risk for each tree in the stand. According to the model’s predictions, thinning from below has a reduced risk of wind damage compared with thinning from above.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"23 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73437000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-24DOI: 10.1093/forestry/cpaa026
Daniela Chequer Charan, C. Pometti, M. Cony, J. Vilardi, B. Saidman, C. Bessega
Prosopis chilensis (Molina) Stuntz (Leguminosae) is a valuable native species in Argentina included in the Prosopis Management Programme. Natural provenances show important height and shape differentiation throughout their distribution in the Monte Desert. The availability of progeny trials provides an opportunity to quantify genetic differentiation among provenances and test the relative importance of demographic vs adaptive processes on morphological variation. We quantified both genetic and quantitative differentiation of neutral markers and five economically important traits, respectively, among four provenances in a provenance-progeny trial. We aimed to quantify the genetic basis of variations in height, basal diameter, tree shape, spine length and biomass. Two hypotheses were tested: (1) economically important traits have significant heritability, and (2) the phenotypic variation among provenances is the result of local adaptation to particular environmental conditions. Our results indicate that most morphological variation was found among individuals within families (~95 per cent). The h2 estimates were heterogeneous among traits and ranged from low (0 for number of stems) to moderate (0.22 and 0.28 for spine length and biomass, respectively). Variance among families (~5 per cent) was evenly distributed within and among provenances. Morphological differentiation among provenances was low, but significant, and could be attributed mainly to individuals from Villa Unión. Based on molecular markers, genetic differentiation among provenances was low and significant (FST = 0.03; P = 5 × 10−4) but was able to differentiate the groups from Villa Unión, Fiambalá and Mogna-Chilecito. Neutrality tests were conducted using the FST –QST test and DJSOST and δGREGORIUS alternative coefficients of differentiation. Neutrality tests yielded no evidence of local adaptation and were rather consistent in showing a trend toward stabilizing selection, particularly for spine length. The selection strategy for breeding programmes should depend on the trait to be improved and should consider both provenance and familiar information. Considering an intra-familiar ranking is encouraged in order to maximize the genetic gain. Additionally, in order to recover germplasm provenance diversity, based on morphological and microsatellite results, our recommendation would be to include seeds from individuals from at least the Villa Unión, Fiambalá and Mogna-Chilecito areas.
{"title":"Genetic variance distribution of SSR markers and economically important quantitative traits in a progeny trial of Prosopis chilensis (Leguminosae): implications for the ‘Algarrobo’ management programme","authors":"Daniela Chequer Charan, C. Pometti, M. Cony, J. Vilardi, B. Saidman, C. Bessega","doi":"10.1093/forestry/cpaa026","DOIUrl":"https://doi.org/10.1093/forestry/cpaa026","url":null,"abstract":"\u0000 Prosopis chilensis (Molina) Stuntz (Leguminosae) is a valuable native species in Argentina included in the Prosopis Management Programme. Natural provenances show important height and shape differentiation throughout their distribution in the Monte Desert. The availability of progeny trials provides an opportunity to quantify genetic differentiation among provenances and test the relative importance of demographic vs adaptive processes on morphological variation. We quantified both genetic and quantitative differentiation of neutral markers and five economically important traits, respectively, among four provenances in a provenance-progeny trial. We aimed to quantify the genetic basis of variations in height, basal diameter, tree shape, spine length and biomass. Two hypotheses were tested: (1) economically important traits have significant heritability, and (2) the phenotypic variation among provenances is the result of local adaptation to particular environmental conditions. Our results indicate that most morphological variation was found among individuals within families (~95 per cent). The h2 estimates were heterogeneous among traits and ranged from low (0 for number of stems) to moderate (0.22 and 0.28 for spine length and biomass, respectively). Variance among families (~5 per cent) was evenly distributed within and among provenances. Morphological differentiation among provenances was low, but significant, and could be attributed mainly to individuals from Villa Unión. Based on molecular markers, genetic differentiation among provenances was low and significant (FST = 0.03; P = 5 × 10−4) but was able to differentiate the groups from Villa Unión, Fiambalá and Mogna-Chilecito. Neutrality tests were conducted using the FST –QST test and DJSOST and δGREGORIUS alternative coefficients of differentiation. Neutrality tests yielded no evidence of local adaptation and were rather consistent in showing a trend toward stabilizing selection, particularly for spine length. The selection strategy for breeding programmes should depend on the trait to be improved and should consider both provenance and familiar information. Considering an intra-familiar ranking is encouraged in order to maximize the genetic gain. Additionally, in order to recover germplasm provenance diversity, based on morphological and microsatellite results, our recommendation would be to include seeds from individuals from at least the Villa Unión, Fiambalá and Mogna-Chilecito areas.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"37 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85852376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-24DOI: 10.1093/forestry/cpaa028
Z. Hosseini, Hooman Latifi, H. Naghavi, Siavash Bakhtiarvand Bakhtiari, F. Fassnacht
Regular biomass estimations for natural and plantation forests are important to support sustainable forestry andto calculate carbon-related statistics. The application of remote sensing data to estimate biomass of forests hasbeen amply demonstrated but there is still space for increasing the efficiency of current approaches. Here, weinvestigated the influence of field plot and sample sizes on the accuracy of random forest models trained withinformation derived from Pleiades very high resolution (VHR) stereo images applied to plantation forests in anarid environment. We collected field data at 311 locations with three different plot area sizes (100, 300 and500 m2). In two experiments, we demonstrate how plot and sample sizes influence the accuracy of biomassestimation models. In the first experiment, we compared model accuracies obtained with varying plot sizes butconstant number of samples. In the second experiment, we fixed the total area to be sampled to account forthe additional effort to collect large field plots. Our results for the first experiment show that model performancemetrics Spearman’s r, RMSErel and RMSEnor improve from 0.61, 0.70 and 0.36 at a sample size of 24–0.79, 0.51and 0.15 at a sample size of 192, respectively. In the second experiment, highest accuracies were obtained witha plot size of 100 m2 (most samples) with Spearman’s r =0.77, RMSErel =0.59 and RMSEnor =0.15. Results froman analysis of variance type-II suggest that the overall most important factors to explain model performancemetrics for our biomass models is sample size. Our results suggest no clear advantage for any plot size to reachaccurate biomass estimates using VHR stereo imagery in plantations. This is an important finding, which partlycontradicts the suggestions of earlier studies but requires validation for other forest types and remote sensingdata types (e.g. LiDAR).
{"title":"Influence of plot and sample sizes on aboveground biomass estimations in plantation forests using very high resolution stereo satellite imagery","authors":"Z. Hosseini, Hooman Latifi, H. Naghavi, Siavash Bakhtiarvand Bakhtiari, F. Fassnacht","doi":"10.1093/forestry/cpaa028","DOIUrl":"https://doi.org/10.1093/forestry/cpaa028","url":null,"abstract":"Regular biomass estimations for natural and plantation forests are important to support sustainable forestry andto calculate carbon-related statistics. The application of remote sensing data to estimate biomass of forests hasbeen amply demonstrated but there is still space for increasing the efficiency of current approaches. Here, weinvestigated the influence of field plot and sample sizes on the accuracy of random forest models trained withinformation derived from Pleiades very high resolution (VHR) stereo images applied to plantation forests in anarid environment. We collected field data at 311 locations with three different plot area sizes (100, 300 and500 m2). In two experiments, we demonstrate how plot and sample sizes influence the accuracy of biomassestimation models. In the first experiment, we compared model accuracies obtained with varying plot sizes butconstant number of samples. In the second experiment, we fixed the total area to be sampled to account forthe additional effort to collect large field plots. Our results for the first experiment show that model performancemetrics Spearman’s r, RMSErel and RMSEnor improve from 0.61, 0.70 and 0.36 at a sample size of 24–0.79, 0.51and 0.15 at a sample size of 192, respectively. In the second experiment, highest accuracies were obtained witha plot size of 100 m2 (most samples) with Spearman’s r =0.77, RMSErel =0.59 and RMSEnor =0.15. Results froman analysis of variance type-II suggest that the overall most important factors to explain model performancemetrics for our biomass models is sample size. Our results suggest no clear advantage for any plot size to reachaccurate biomass estimates using VHR stereo imagery in plantations. This is an important finding, which partlycontradicts the suggestions of earlier studies but requires validation for other forest types and remote sensingdata types (e.g. LiDAR).","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"9 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73444274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-08DOI: 10.1093/forestry/cpaa022
G. Georgiev, J. Rousselet, M. Laparie, C. Robinet, M. Georgieva, G. Zaemdzhikova, A. Roques, Alexis Bernard, Laura Poitou, M. Buradino, C. Kerdelhué, J. Rossi, M. Matova, P. Boyadzhiev, P. Mirchev
To investigate enemy pressure across the range of the pine processionary moth (Thaumetopoea pityocampa, Den. & Schiff.) as it spreads northwards in Europe because of climate change, a survey of 206 egg batches from historical and newly colonized areas at both the westernmost and the easternmost ends of the front was carried out in 2016–2018. Out of them, 97 egg batches were collected from nine locations in three regions in France and 109 from four localities in two regions in Bulgaria, both within historical and newly colonized ranges of the pest. The average number of eggs per batch collected in Bulgaria (226.6 ± 43.2) was higher than that in France (194.3 ± 50.1). However, the hatching percentage was higher in French samples, varying from 69.8 to 95.7, vs 49.8 to 85.2 per cent in Bulgarian samples. Four primary parasitoids (Ooencyrtus pityocampae, Baryscapus servadeii, Anastatus bifasciatus, Trichogramma sp.) and a hyperparasitoid (Baryscapus transversalis, found only in two regions of the historical range in Bulgaria) were identified. The oligophagous species B. servadeii was present at all sites within the historical range of the pest. In newly colonized areas, the impact of primary parasitoids on the host was distinctly low, suggesting that they lag behind the range expansion of pine processionary moth. In France, the most abundant species in the T. pityocampa parasitoid complex were B. servadeii in Ré Island and Orléans (97.3 and 87.4 per cent, respectively), and Trichogramma sp. (99.7 per cent) in a newly colonized locality in Fréhel. Ooencyrtus pityocampae prevailed in three of four Bulgarian localities (72.1 per cent in Sandanski, 89.7 per cent in Maglizh and 65.7 per cent in Sladak kladenets), whereas B. servadeii was the most abundant in Gega (75.4 per cent). Mortality of B. servadeii and O. pityocampae caused by the hyperparasitoid B. transversalis amounted to 4.8–6.2 per cent. The impact of predators on the pine processionary moth in the egg stage was negligible at most sites, reaching 12.5 per cent in only one site (Maglizh).
{"title":"Comparative studies of egg parasitoids of the pine processionary moth (Thaumetopoea pityocampa, Den. & Schiff.) in historic and expansion areas in France and Bulgaria","authors":"G. Georgiev, J. Rousselet, M. Laparie, C. Robinet, M. Georgieva, G. Zaemdzhikova, A. Roques, Alexis Bernard, Laura Poitou, M. Buradino, C. Kerdelhué, J. Rossi, M. Matova, P. Boyadzhiev, P. Mirchev","doi":"10.1093/forestry/cpaa022","DOIUrl":"https://doi.org/10.1093/forestry/cpaa022","url":null,"abstract":"\u0000 To investigate enemy pressure across the range of the pine processionary moth (Thaumetopoea pityocampa, Den. & Schiff.) as it spreads northwards in Europe because of climate change, a survey of 206 egg batches from historical and newly colonized areas at both the westernmost and the easternmost ends of the front was carried out in 2016–2018. Out of them, 97 egg batches were collected from nine locations in three regions in France and 109 from four localities in two regions in Bulgaria, both within historical and newly colonized ranges of the pest. The average number of eggs per batch collected in Bulgaria (226.6 ± 43.2) was higher than that in France (194.3 ± 50.1). However, the hatching percentage was higher in French samples, varying from 69.8 to 95.7, vs 49.8 to 85.2 per cent in Bulgarian samples. Four primary parasitoids (Ooencyrtus pityocampae, Baryscapus servadeii, Anastatus bifasciatus, Trichogramma sp.) and a hyperparasitoid (Baryscapus transversalis, found only in two regions of the historical range in Bulgaria) were identified. The oligophagous species B. servadeii was present at all sites within the historical range of the pest. In newly colonized areas, the impact of primary parasitoids on the host was distinctly low, suggesting that they lag behind the range expansion of pine processionary moth. In France, the most abundant species in the T. pityocampa parasitoid complex were B. servadeii in Ré Island and Orléans (97.3 and 87.4 per cent, respectively), and Trichogramma sp. (99.7 per cent) in a newly colonized locality in Fréhel. Ooencyrtus pityocampae prevailed in three of four Bulgarian localities (72.1 per cent in Sandanski, 89.7 per cent in Maglizh and 65.7 per cent in Sladak kladenets), whereas B. servadeii was the most abundant in Gega (75.4 per cent). Mortality of B. servadeii and O. pityocampae caused by the hyperparasitoid B. transversalis amounted to 4.8–6.2 per cent. The impact of predators on the pine processionary moth in the egg stage was negligible at most sites, reaching 12.5 per cent in only one site (Maglizh).","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"11 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88929414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-26DOI: 10.1093/forestry/cpaa019
Ting-Ru Yang, J. Kershaw, M. Ducey
Light detection and ranging (LiDAR) is used to estimate tree, stand and forest characteristics across large geographic areas. In most analyses, several independent LiDAR-based allometric equations are built to predict various forest attributes. When each forest attribute is estimated independently, there is potential for predictions of forest attributes that are not mathematically or biologically consistent. Combined allometric equations can be considered a system of equations describing the stand structure. Mathematically compatible and biologically meaningful estimates can be derived by estimating key structural variables and solving for other components, rather than estimating each forest attribute separately and independently. In this study, we propose the development of a system of allometric equations describing the relationship between volume per unit area, Lorey’s average height, basal area, quadratic mean diameter (QMD) and density. The system of allometric equations is derived from extensive field data. Key structural attributes are predicted using LiDAR metrics, and the remaining structural variables are solved for using the system of allometric equations. Predictions of structural attributes from the system of allometric equations are compared with predictions from independent LiDAR-derived prediction equations. Results showed that applying the systems approach can provide reasonable and compatible estimates with lower required sample sizes, especially when multiple attributes need to be considered simultaneously. Testing the portability of the systems approach in more complex stand structures and across different LiDAR acquisitions will be required in the future.
{"title":"The development of allometric systems of equations for compatible area-based LiDAR-assisted estimation","authors":"Ting-Ru Yang, J. Kershaw, M. Ducey","doi":"10.1093/forestry/cpaa019","DOIUrl":"https://doi.org/10.1093/forestry/cpaa019","url":null,"abstract":"\u0000 Light detection and ranging (LiDAR) is used to estimate tree, stand and forest characteristics across large geographic areas. In most analyses, several independent LiDAR-based allometric equations are built to predict various forest attributes. When each forest attribute is estimated independently, there is potential for predictions of forest attributes that are not mathematically or biologically consistent. Combined allometric equations can be considered a system of equations describing the stand structure. Mathematically compatible and biologically meaningful estimates can be derived by estimating key structural variables and solving for other components, rather than estimating each forest attribute separately and independently. In this study, we propose the development of a system of allometric equations describing the relationship between volume per unit area, Lorey’s average height, basal area, quadratic mean diameter (QMD) and density. The system of allometric equations is derived from extensive field data. Key structural attributes are predicted using LiDAR metrics, and the remaining structural variables are solved for using the system of allometric equations. Predictions of structural attributes from the system of allometric equations are compared with predictions from independent LiDAR-derived prediction equations. Results showed that applying the systems approach can provide reasonable and compatible estimates with lower required sample sizes, especially when multiple attributes need to be considered simultaneously. Testing the portability of the systems approach in more complex stand structures and across different LiDAR acquisitions will be required in the future.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"19 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86601453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-24DOI: 10.1093/forestry/cpaa017
Raúl Armando Ramos Veintimilla, D. MacFarlane, Lauren Cooper
‘Analog’ forestry is a novel silvicultural approach for reforestation of degraded land that seeks to establish trees that are analogous in structure and ecological function to the original climax or subclimax vegetation of the region where they are planted. Analog forestry aims to strengthen rural communities, both socially and economically, with tree plantings of high biodiversity, which provide commercial products and resiliency, while avoiding agrochemicals and fossil fuels. The latter links this strategy to climate change mitigation and adaptation strategies, but there has been little analysis comparing the potential for above- and below-ground carbon storage in analog forests, as compared with more typical reforestation efforts via single-species plantations. We present the results of a study to estimate carbon sequestration levels, above- and below-ground, from an experimental analog forest system and a teak (Tectona grandis L.f.) plantation system, in comparison with a degraded pasture system. The study found that the analog and teak plantation forest systems stored higher quantities of total carbon (178 and 141 t C ha−1, respectively), when compared with a degraded pasture system (124 t C ha−1). However, the teak plantation had decreased soil carbon stocks, relative to the degraded pasture. The analog forest had the best balance of both above- and below-ground carbon stored over the 17-year study period and provided a more diverse array of timber and non-timber forest products when compared with the teak plantation. This suggests that analog forestry could be a viable social–ecological approach to carbon storage and reforestation in the study region and other places with large areas of degraded pasture and a good understanding of the structure and function of the original vegetation.
“模拟”林业是一种新的造林方法，用于退化土地的再造林，旨在建立在结构和生态功能上类似于原始顶极或次顶极植被的树木。模拟林业旨在通过种植高生物多样性的树木，在社会和经济上加强农村社区，提供商业产品和弹性，同时避免使用农用化学品和化石燃料。后者将这一战略与气候变化减缓和适应战略联系起来，但是很少有分析将模拟森林的地上和地下碳储存潜力与通过单一物种种植园进行的更典型的再造林工作进行比较。我们提出了一项研究的结果，以估计从实验模拟森林系统和柚木(Tectona grandis L.f.)人工林系统的地上和地下碳固存水平，并将其与退化的牧场系统进行比较。研究发现，与退化的牧场系统(124 t C ha - 1)相比，模拟和柚木人工林系统储存的总碳量更高(分别为178和141 t C ha - 1)。与退化草地相比，柚木人工林土壤碳储量明显减少。与柚木人工林相比，模拟森林在17年的研究期间具有最佳的地上和地下碳储量平衡，并提供更多样化的木材和非木材林产品。这表明，在研究区和其他有大面积退化牧场和对原始植被的结构和功能有很好的了解的地方，模拟林业可能是一种可行的社会生态碳储存和再造林方法。
{"title":"The carbon sequestration potential of ‘analog’ forestry in Ecuador: an alternative strategy for reforestation of degraded pastures","authors":"Raúl Armando Ramos Veintimilla, D. MacFarlane, Lauren Cooper","doi":"10.1093/forestry/cpaa017","DOIUrl":"https://doi.org/10.1093/forestry/cpaa017","url":null,"abstract":"\u0000 ‘Analog’ forestry is a novel silvicultural approach for reforestation of degraded land that seeks to establish trees that are analogous in structure and ecological function to the original climax or subclimax vegetation of the region where they are planted. Analog forestry aims to strengthen rural communities, both socially and economically, with tree plantings of high biodiversity, which provide commercial products and resiliency, while avoiding agrochemicals and fossil fuels. The latter links this strategy to climate change mitigation and adaptation strategies, but there has been little analysis comparing the potential for above- and below-ground carbon storage in analog forests, as compared with more typical reforestation efforts via single-species plantations. We present the results of a study to estimate carbon sequestration levels, above- and below-ground, from an experimental analog forest system and a teak (Tectona grandis L.f.) plantation system, in comparison with a degraded pasture system. The study found that the analog and teak plantation forest systems stored higher quantities of total carbon (178 and 141 t C ha−1, respectively), when compared with a degraded pasture system (124 t C ha−1). However, the teak plantation had decreased soil carbon stocks, relative to the degraded pasture. The analog forest had the best balance of both above- and below-ground carbon stored over the 17-year study period and provided a more diverse array of timber and non-timber forest products when compared with the teak plantation. This suggests that analog forestry could be a viable social–ecological approach to carbon storage and reforestation in the study region and other places with large areas of degraded pasture and a good understanding of the structure and function of the original vegetation.","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"52 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91193953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-03DOI: 10.1093/forestry/cpaa018
J. Dahlen, M. Nabavi, D. Auty, L. Schimleck, T. Eberhardt
1Warnell School of Forestry and Natural Resources, University of Georgia, 180 E Green St, Athens, Georgia, 30602, USA 2School of Forestry, Northern Arizona University, 200 East Pine Knoll Drive, Flagstaff, Arizona, 86011, USA 3Wood Science and Engineering, Oregon State University, 119 Richardson Hall, Corvallis, Oregon, 97331, USA 4Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive, Madison, WI, 53726, USA
{"title":"Models for predicting the within-tree and regional variation of tracheid length and width for plantation loblolly pine","authors":"J. Dahlen, M. Nabavi, D. Auty, L. Schimleck, T. Eberhardt","doi":"10.1093/forestry/cpaa018","DOIUrl":"https://doi.org/10.1093/forestry/cpaa018","url":null,"abstract":"1Warnell School of Forestry and Natural Resources, University of Georgia, 180 E Green St, Athens, Georgia, 30602, USA 2School of Forestry, Northern Arizona University, 200 East Pine Knoll Drive, Flagstaff, Arizona, 86011, USA 3Wood Science and Engineering, Oregon State University, 119 Richardson Hall, Corvallis, Oregon, 97331, USA 4Forest Products Laboratory, USDA Forest Service, One Gifford Pinchot Drive, Madison, WI, 53726, USA","PeriodicalId":12342,"journal":{"name":"Forestry","volume":"3 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2020-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78676984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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