We examined the effect of thinning on wood quality of western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis) located on Prince of Wales and Mitkof Islands in southeast Alaska. Sample trees came from paired plots (thinned versus unthinned) in eight naturally regenerated, mixed stands of young-growth western hemlock and Sitka spruce in an effort to examine a range of thinning densities, from 10 X 10 ft to 20 X 20 ft spacing. The stands, which had been thinned in the late 1970s and early 1980s, ranged in age from 36 to 73 years at the time they were selected for this study in 2003. The main focus of the stand selection in this retrospective study was to find individual stands that included a thinned plot and an adjacent unthinned plot from the same original stand. A random sample of trees from both thinned and unthinned plots was selected, stratified by tree dbh. About 12 trees per species per stand (461 trees in total) were selected for the study. Selected trees were harvested, and a lumber recovery study was conducted, enabling us to relate log volume to recovered lumber volume by product grade. Surfaced dry dimension lumber was produced, graded, and nondestructively tested using the transverse E-vibration standard test for stiffness. We did not evaluate the resource for appearance-grade products. For each species, the overall treatment effect (thinned versus unthinned) on lumber grade recovery and transverse E-vibration modulus of elasticity by vertical-log position (butt log, middle log, or top log) were analyzed using a mixed-effects procedure. Results suggest that there were no significant differences in product recovery or value between the thinned plots and the untreated control plots in the manufacture of structural lumber products.
研究了阿拉斯加东南部威尔士王子岛和米特考夫岛的西部铁杉(Tsuga heterophylla)和锡特卡云杉(Picea sitchensis)的间伐对木材质量的影响。样本树来自8个自然再生的年轻西部铁杉和西特卡云杉混合林分的成对样地(疏林和未疏林)，以检验疏林密度的范围，从10 X 10英尺到20 X 20英尺的间距。这些在20世纪70年代末和80年代初被砍伐的树木，在2003年被选为这项研究的对象时，年龄从36岁到73岁不等。在回顾性研究中，林分选择的主要重点是寻找来自同一原始林分的包括疏林样地和相邻未疏林样地的单个林分。随机从稀疏和未稀疏的地块中选择树木样本，按树径分层。每林分每种树约12棵(共461棵)。选定的树木被采伐，并进行了木材回收研究，使我们能够通过产品等级将原木体积与回收木材体积联系起来。表面干燥尺寸的木材被生产，分级，并使用横向e振动标准测试刚度的无损测试。我们没有评估外观级产品的资源。对于每个树种，使用混合效应程序分析了垂直原木位置(对接原木、中间原木或顶部原木)对木材等级恢复和横向e -振动弹性模量的总体处理效果(减薄与未减薄)。结果表明，在结构木材产品的生产中，稀薄地块与未经处理的对照地块之间的产品回收率或价值没有显着差异。
{"title":"Evaluating effects of thinning on wood quality in southeast Alaska","authors":"E. Lowell, D. Dykstra, R. Monserud","doi":"10.5849/WJAF.11-019","DOIUrl":"https://doi.org/10.5849/WJAF.11-019","url":null,"abstract":"We examined the effect of thinning on wood quality of western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis) located on Prince of Wales and Mitkof Islands in southeast Alaska. Sample trees came from paired plots (thinned versus unthinned) in eight naturally regenerated, mixed stands of young-growth western hemlock and Sitka spruce in an effort to examine a range of thinning densities, from 10 X 10 ft to 20 X 20 ft spacing. The stands, which had been thinned in the late 1970s and early 1980s, ranged in age from 36 to 73 years at the time they were selected for this study in 2003. The main focus of the stand selection in this retrospective study was to find individual stands that included a thinned plot and an adjacent unthinned plot from the same original stand. A random sample of trees from both thinned and unthinned plots was selected, stratified by tree dbh. About 12 trees per species per stand (461 trees in total) were selected for the study. Selected trees were harvested, and a lumber recovery study was conducted, enabling us to relate log volume to recovered lumber volume by product grade. Surfaced dry dimension lumber was produced, graded, and nondestructively tested using the transverse E-vibration standard test for stiffness. We did not evaluate the resource for appearance-grade products. For each species, the overall treatment effect (thinned versus unthinned) on lumber grade recovery and transverse E-vibration modulus of elasticity by vertical-log position (butt log, middle log, or top log) were analyzed using a mixed-effects procedure. Results suggest that there were no significant differences in product recovery or value between the thinned plots and the untreated control plots in the manufacture of structural lumber products.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"11 1","pages":"72-83"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5849/WJAF.11-019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jacob L. Strunk, S. Reutebuch, H. Andersen, P. Gould, R. McGaughey
Previous studies have demonstrated that light detection and ranging (LiDAR)-derived variables can be used to model forest yield variables, such as biomass, volume, and number of stems. However, the next step is underrepresented in the literature: estimation of forest yield with appropriate confidence intervals. It is of great importance that the procedures required for conducting forest inventory with LiDAR and the estimation precision of such procedures are sufficiently documented to enable their evaluation and implementation by land managers. In this study, we demonstrated the regression estimator, a model-assisted estimator (approximately design-unbiased), using LiDAR-derived variables for estimation of total forest yield. The LiDAR-derived variables are statistics associated with vegetation height and cover. The estimation procedure requires complete coverage of the forest with LiDAR and a random sample of precisely georeferenced field measurement plots. Regression estimation relies on sample-based ordinary least squares (OLS) regression models relating forest yield and LiDAR-derived variables. Estimation was performed using the OLS models and LiDAR-derived variables for the entire population. Regression estimates of basal area, volume, stand density, and biomass were much more precise than simple random sampling estimates (design effects were 0.25, 0.24, 0.44, and 0.27, respectively).
{"title":"Model-Assisted Forest Yield Estimation with Light Detection and Ranging","authors":"Jacob L. Strunk, S. Reutebuch, H. Andersen, P. Gould, R. McGaughey","doi":"10.5849/WJAF.10-043","DOIUrl":"https://doi.org/10.5849/WJAF.10-043","url":null,"abstract":"Previous studies have demonstrated that light detection and ranging (LiDAR)-derived variables can be used to model forest yield variables, such as biomass, volume, and number of stems. However, the next step is underrepresented in the literature: estimation of forest yield with appropriate confidence intervals. It is of great importance that the procedures required for conducting forest inventory with LiDAR and the estimation precision of such procedures are sufficiently documented to enable their evaluation and implementation by land managers. In this study, we demonstrated the regression estimator, a model-assisted estimator (approximately design-unbiased), using LiDAR-derived variables for estimation of total forest yield. The LiDAR-derived variables are statistics associated with vegetation height and cover. The estimation procedure requires complete coverage of the forest with LiDAR and a random sample of precisely georeferenced field measurement plots. Regression estimation relies on sample-based ordinary least squares (OLS) regression models relating forest yield and LiDAR-derived variables. Estimation was performed using the OLS models and LiDAR-derived variables for the entire population. Regression estimates of basal area, volume, stand density, and biomass were much more precise than simple random sampling estimates (design effects were 0.25, 0.24, 0.44, and 0.27, respectively).","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"53-59"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5849/WJAF.10-043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is concern that intensive even-aged forest management in conifer plantations has resulted in the decline of plant species diversity and contributed to the rise of invasive species in western forests. This 3-year study assessed plant species richness, composition of vascular plant species, and presence of rare and nonnative plant species in 73 survey units (2,528 ac) on industrial forestland in northern California. Survey units were evenly divided between conifer plantations and adjacent managed uneven-aged forests in three regions of northern California: Sierra Nevada, Southern Cascades, and Klamath Mountains. We surveyed two forest types within these regions: mixed conifer and true fir. There was no significant difference in species richness between plantations and adjacent forests. Plantations tended to be richer in forbs and graminoids, whereas forests were richer in trees and shrubs. Herbicide applications in plantations significantly reduced shrub species richness, but the effect was short-lived. Rare plant species were equally distributed between plantations and adjacent forests, but plantations contained one additional nonnative plant species. Overall, our findings demonstrate that managed, even-aged conifer plantations maintain plant species richness at a level similar to adjacent managed, uneven-aged forests.
{"title":"Comparison of floristic diversity between young conifer plantations and second-growth adjacent forests in California's northern interior.","authors":"Cajun E. James, Bruce Krumland, D. Taylor","doi":"10.5849/WJAF.11-006","DOIUrl":"https://doi.org/10.5849/WJAF.11-006","url":null,"abstract":"There is concern that intensive even-aged forest management in conifer plantations has resulted in the decline of plant species diversity and contributed to the rise of invasive species in western forests. This 3-year study assessed plant species richness, composition of vascular plant species, and presence of rare and nonnative plant species in 73 survey units (2,528 ac) on industrial forestland in northern California. Survey units were evenly divided between conifer plantations and adjacent managed uneven-aged forests in three regions of northern California: Sierra Nevada, Southern Cascades, and Klamath Mountains. We surveyed two forest types within these regions: mixed conifer and true fir. There was no significant difference in species richness between plantations and adjacent forests. Plantations tended to be richer in forbs and graminoids, whereas forests were richer in trees and shrubs. Herbicide applications in plantations significantly reduced shrub species richness, but the effect was short-lived. Rare plant species were equally distributed between plantations and adjacent forests, but plantations contained one additional nonnative plant species. Overall, our findings demonstrate that managed, even-aged conifer plantations maintain plant species richness at a level similar to adjacent managed, uneven-aged forests.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"60-71"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5849/WJAF.11-006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The forest industry is constantly changing, and technology is constantly shifting the bar for efficiency and profitability. To maintain competitiveness and control costs in a global market, an efficient log tracking method must be used by regional stakeholders in the log supply chain from stump to mill to end consumer. It is important to understand the implications of recent innovations in log tracking for stakeholders in the Pacific Northwest in the context of a global economy, and how innovations in other regions may affect the future of log tracking. In this report, we (1) discuss the importance of log tracking technology, (2) review both regional and international efforts to harness technology for tracking logs from stump to mill, (3) report on a regional survey that examines the current status of log tracking in the Pacific Northwest, and (4) identify the most promising technologies that could be implemented in the near future. The majority of regional stakeholders use paper tags or other relatively simple tagging methods. Radio frequency identification (RFID) tags and other tracer technologies were not used when marking, sorting, tracking, or paying for logs by any of the regional organizations responding to the survey. RFID tags and spray-on code marking show promise for the near future.
{"title":"Current and Potential Tagging and Tracking Systems for Logs Harvested from Pacific Northwest Forests","authors":"G. Murphy, J. Clark, S. Pilkerton","doi":"10.5849/WJAF.11-027","DOIUrl":"https://doi.org/10.5849/WJAF.11-027","url":null,"abstract":"The forest industry is constantly changing, and technology is constantly shifting the bar for efficiency and profitability. To maintain competitiveness and control costs in a global market, an efficient log tracking method must be used by regional stakeholders in the log supply chain from stump to mill to end consumer. It is important to understand the implications of recent innovations in log tracking for stakeholders in the Pacific Northwest in the context of a global economy, and how innovations in other regions may affect the future of log tracking. In this report, we (1) discuss the importance of log tracking technology, (2) review both regional and international efforts to harness technology for tracking logs from stump to mill, (3) report on a regional survey that examines the current status of log tracking in the Pacific Northwest, and (4) identify the most promising technologies that could be implemented in the near future. The majority of regional stakeholders use paper tags or other relatively simple tagging methods. Radio frequency identification (RFID) tags and other tracer technologies were not used when marking, sorting, tracking, or paying for logs by any of the regional organizations responding to the survey. RFID tags and spray-on code marking show promise for the near future.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"84-91"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5849/WJAF.11-027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Field Note: Efficiency of Sampling Tree Regeneration with Two Plot Sizes in Northern Arizona","authors":"Joshua J. Puhlick","doi":"10.5849/WJAF.10-039","DOIUrl":"https://doi.org/10.5849/WJAF.10-039","url":null,"abstract":"","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"100-101"},"PeriodicalIF":0.0,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5849/WJAF.10-039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70979340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Site index, estimated as a function of dominant-tree height and age, is often used as an expression of site quality. This expression is assumed to be effectively independent of stand density. Observation of dominant height at two different ponderosa pine levels-of-growing-stock studies revealed that top height stability with respect to stand density depends on the definition of the dominant height. Dominant height estimates calculated from a fixed number of trees per acre (ranging from 10 to 60 of the tallest trees per acre) were less affected by density than those calculated from a proportion (with the cutoff ranging from 95th to the 70th percentile) of the largest trees in the stand.
{"title":"Effects of stand density on top height estimation for ponderosa pine","authors":"M. Ritchie, Jianwei Zhang, T. Hamilton","doi":"10.1093/WJAF/27.1.18","DOIUrl":"https://doi.org/10.1093/WJAF/27.1.18","url":null,"abstract":"Site index, estimated as a function of dominant-tree height and age, is often used as an expression of site quality. This expression is assumed to be effectively independent of stand density. Observation of dominant height at two different ponderosa pine levels-of-growing-stock studies revealed that top height stability with respect to stand density depends on the definition of the dominant height. Dominant height estimates calculated from a fixed number of trees per acre (ranging from 10 to 60 of the tallest trees per acre) were less affected by density than those calculated from a proportion (with the cutoff ranging from 95th to the 70th percentile) of the largest trees in the stand.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"18-24"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/WJAF/27.1.18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61109232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. N. Filipescu, A. Groot, D. Macisaac, M. Cruickshank, J. D. Stewart
{"title":"Prediction of Diameter Using Height and Crown Attributes: A Case Study","authors":"C. N. Filipescu, A. Groot, D. Macisaac, M. Cruickshank, J. D. Stewart","doi":"10.1093/WJAF/27.1.30","DOIUrl":"https://doi.org/10.1093/WJAF/27.1.30","url":null,"abstract":"","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"30-35"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/WJAF/27.1.30","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61109245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the recent surge in the use of mastication as a fuel treatment option, few studies have been conducted on potential fire behavior or fire effects associated with mastication or combined masticated/fire treatments (Stephens and Moghaddas 2005, Glitzenstein et al. 2006, Kobziar et al. 2009). Fuel models representing masticated fuel conditions for use in fire behavior modeling have not been well developed at the time of this publication (Glitzenstein et al. 2006, Kane et al. 2009, Battaglia et al. 2010). Fires in masticated fuels when soil is dry can produce heat above lethal levels for plant roots (Busse et al. 2010). An understanding of likely ecological effects should be made available to managers planning to use mastication as a fuel treatment. Mastication used in combination with prescribed burning can reduce both canopy and surface fuel loads (Stephens and Moghaddas 2005, Reiner et al. 2009). However, in young, dense plantations, such as the one in this study, managers are often concerned with whether tree mortality associated with burning residual mastication fuels outweighs the benefits of further reductions in potential fire behavior. Managers are also interested in whether pulling masticated fuel away from tree boles would decrease mortality from prescribed burning. This study should aid in decisionmaking regarding these management options. This study quantified tree mortality and compared potential wildfire behavior between treatment conditions in a young ponderosa pine (Pinus ponderosa C. Lawson) plantation in the southern Sierra Nevada in California. Tree mortality results were based on field data. Baseline tree mortality data were gathered after the mastication treatment but before the prescribed burn treatment (postmastication/preburn). Postmastication-and-fire tree mortality data were gathered for two growing seasons after the prescribed fire treatments were completed, allowing for conclusions to be drawn on the tree mortality effects of prescribed burning residual mastication fuels. Modeled results were intended to reflect potential wildfire behavior immediately posttreatment to allow land managers to weigh the risk of potentially extreme wildfire behavior against tree mortality from these types of these treatments.
尽管最近将咀嚼作为一种燃料处理方法的使用激增，但很少有研究对咀嚼或咀嚼/火灾联合治疗相关的潜在火灾行为或火灾效应进行研究(Stephens和Moghaddas 2005, Glitzenstein等人2006,Kobziar等人2009)。在本文发表时，用于火灾行为建模的燃料模型尚未得到很好的发展(Glitzenstein等人2006年，Kane等人2009年，Battaglia等人2010年)。当土壤干燥时，在咀嚼燃料中燃烧可以产生高于植物根系致死水平的热量(Busse et al. 2010)。应使计划使用咀嚼作为燃料处理的管理人员了解可能的生态影响。咀嚼与规定燃烧相结合可以减少冠层和表面燃料负荷(Stephens and Moghaddas 2005, Reiner et al. 2009)。然而，在年轻、茂密的种植园中，如本研究中的种植园，管理者经常关心的是，燃烧残余咀嚼燃料导致的树木死亡率是否超过了进一步减少潜在火灾行为的好处。管理人员还感兴趣的是，从树洞中取出咀嚼过的燃料是否会降低规定燃烧造成的死亡率。这项研究应该有助于这些管理方案的决策。本研究量化了树木死亡率，并比较了加州内华达山脉南部一个黄松(Pinus ponderosa C. Lawson)幼松种植园不同处理条件下潜在的野火行为。树木死亡率结果基于实地数据。基线树木死亡率数据在咀嚼治疗后但在规定的烧伤治疗(咀嚼后/烧伤前)之前收集。在完成规定的火灾处理后，收集了两个生长季节的咀嚼和火灾后树木死亡率数据，从而得出规定燃烧残余咀嚼燃料对树木死亡率影响的结论。建模结果旨在反映处理后立即发生的潜在野火行为，以使土地管理者能够权衡这些类型的处理造成的潜在极端野火行为的风险与树木死亡率。
{"title":"Mastication and Prescribed Fire Influences on Tree Mortality and Predicted Fire Behavior in Ponderosa Pine","authors":"A. Reiner, N. Vaillant, Scott N. Dailey","doi":"10.1093/WJAF/27.1.36","DOIUrl":"https://doi.org/10.1093/WJAF/27.1.36","url":null,"abstract":"Despite the recent surge in the use of mastication as a fuel treatment option, few studies have been conducted on potential fire behavior or fire effects associated with mastication or combined masticated/fire treatments (Stephens and Moghaddas 2005, Glitzenstein et al. 2006, Kobziar et al. 2009). Fuel models representing masticated fuel conditions for use in fire behavior modeling have not been well developed at the time of this publication (Glitzenstein et al. 2006, Kane et al. 2009, Battaglia et al. 2010). Fires in masticated fuels when soil is dry can produce heat above lethal levels for plant roots (Busse et al. 2010). An understanding of likely ecological effects should be made available to managers planning to use mastication as a fuel treatment. Mastication used in combination with prescribed burning can reduce both canopy and surface fuel loads (Stephens and Moghaddas 2005, Reiner et al. 2009). However, in young, dense plantations, such as the one in this study, managers are often concerned with whether tree mortality associated with burning residual mastication fuels outweighs the benefits of further reductions in potential fire behavior. Managers are also interested in whether pulling masticated fuel away from tree boles would decrease mortality from prescribed burning. This study should aid in decisionmaking regarding these management options. This study quantified tree mortality and compared potential wildfire behavior between treatment conditions in a young ponderosa pine (Pinus ponderosa C. Lawson) plantation in the southern Sierra Nevada in California. Tree mortality results were based on field data. Baseline tree mortality data were gathered after the mastication treatment but before the prescribed burn treatment (postmastication/preburn). Postmastication-and-fire tree mortality data were gathered for two growing seasons after the prescribed fire treatments were completed, allowing for conclusions to be drawn on the tree mortality effects of prescribed burning residual mastication fuels. Modeled results were intended to reflect potential wildfire behavior immediately posttreatment to allow land managers to weigh the risk of potentially extreme wildfire behavior against tree mortality from these types of these treatments.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"36-41"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/WJAF/27.1.36","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61109255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Snags and hardwoods contribute to biological, structural, and functional diversity in old-growth forests. In the US Pacific Northwest, only general knowledge about regional patterns is available to determine target density of snags and hardwood trees. To investigate their variability at relevant scales for silviculture, we examined snag and hardwood densities and sizes in 20 old-growth units in northern and southern aspects in the Coast Range and the Willamette Valley foothills of Oregon. Snag densities varied largely between subregions and aspects, with aspect affecting densities more than subregion. In the Coast Range, snag density was 2.8 times greater on northern aspects than on southern aspects, whereas in the Willamette Valley foothills snag density was 1.4 times greater on northern aspects than on southern aspects. Density of snags larger than 101.6 cm in diameter was very low. Hardwood densities were also greater on northern aspects than on southern aspects. The negative exponential distribution of hardwood density frequency by size classes could be explained by cohort growth under a wide range of competitive pressures or repeated-recruitment events. Aspect and subregion should be taken into account when defining management targets. Allowing for flexibility at these smaller spatial scales would better reflect the variability in ecological conditions and land use history that led to the development of old-growth stands.
{"title":"Mesoscale Variation in Snag and Hardwood Densities and Sizes in Old-Growth Forests in Western Oregon","authors":"A. Ares, Cheryl A. Bright, K. Puettmann","doi":"10.1093/WJAF/27.1.12","DOIUrl":"https://doi.org/10.1093/WJAF/27.1.12","url":null,"abstract":"Snags and hardwoods contribute to biological, structural, and functional diversity in old-growth forests. In the US Pacific Northwest, only general knowledge about regional patterns is available to determine target density of snags and hardwood trees. To investigate their variability at relevant scales for silviculture, we examined snag and hardwood densities and sizes in 20 old-growth units in northern and southern aspects in the Coast Range and the Willamette Valley foothills of Oregon. Snag densities varied largely between subregions and aspects, with aspect affecting densities more than subregion. In the Coast Range, snag density was 2.8 times greater on northern aspects than on southern aspects, whereas in the Willamette Valley foothills snag density was 1.4 times greater on northern aspects than on southern aspects. Density of snags larger than 101.6 cm in diameter was very low. Hardwood densities were also greater on northern aspects than on southern aspects. The negative exponential distribution of hardwood density frequency by size classes could be explained by cohort growth under a wide range of competitive pressures or repeated-recruitment events. Aspect and subregion should be taken into account when defining management targets. Allowing for flexibility at these smaller spatial scales would better reflect the variability in ecological conditions and land use history that led to the development of old-growth stands.","PeriodicalId":51220,"journal":{"name":"Western Journal of Applied Forestry","volume":"27 1","pages":"12-17"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/WJAF/27.1.12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61109222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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