Annals of Forest Science最新文献

Evolving societal demands and accelerated ecological dynamics due to global change are rapidly altering forest ecosystems and their services. This has prompted the need for advancing forest inventorying and monitoring initatives to expand their scope, improve data collection, foster scientific understanding, and better inform policy responses. Here, we discuss the collaborative processes followed to develop an Advanced Inventorying and Monitoring (AIM) system for Swiss forests. Further, we provide the key messages that emerged from this process which can be of interest to those involved in similar processes at the national/international level.

Key message

We elucidated the age trends of narrow-sense heritability and phenotypic/genetic correlations and the age–age genetic correlation of growth ring components of Cryptomeria japonica D. Don by investigating progenies of controlled crossings by soft X-ray densitometry analysis. Wood density in the C. japonica breeding program can be efficiently improved by selecting trees with a higher earlywood density and latewood percentage as early as forest stand ages of 5–9 years.

Context

Wood density within the trunk is affected by the intra-ring wood density profile and its age trend from pith to bark. Wood density can be efficiently improved by clarifying whether wood density and highly correlated intra-ring components are under additive genetic control.

Aims

The aim of this study was to elucidate the age trends of narrow-sense heritability and phenotypic/genetic correlations of growth ring components and investigate the possibility of early selection for improving wood density in Cryptomeria japonica.

Methods

We quantified seven growth ring components (width, density, earlywood/latewood width, average earlywood/latewood density, and latewood percentage) for 5112 annual rings of 342 18-year-old trees derived from 24 controlled pollinated full-sib families of C. japonica plus tree clones by soft X-ray densitometry analysis. Genetic parameters and correlations among the seven growth ring components were analyzed using a linear mixed model and the breedR package.

Results

Earlywood density and latewood percentage exhibited a higher phenotypic and genetic correlation with ring density than the other ring components at almost all ages. Earlywood density and latewood percentage exhibited a lower correlation with ring width than the other ring components after a stand age of 5 years. The age–age genetic correlation of earlywood density and latewood percentage was 0.70 for a stand age of 17 years and was strong at stand ages of 5 and 9 years.

Conclusion

Efforts focusing on improving earlywood density and latewood percentage may contribute to improving wood density efficiently in tree breeding programs for C. japonica. Traits related to the ring density of C. japonica trees can possibly be selected as early as stand ages of 5–9 years, and the required period for progeny selection may be substantially shortened when selecting trees with high wood density.

Key message

Drought severely worsened till 2100 and eventually outplayed growth-enhancing CO₂ fertilization turning productivity gains into losses for beech and fir. Most scenarios generated notable losses in profitability but economic tipping points were later than for productivity due to lag effects related to discounting. Time mixture of fir and shortening rotation can counteract economic risks under climate change, but requires early admixture and moderate establishment costs.

Context

Adaptation strategies to climate change (CC) such as establishing mixed forests are often based on ecological understanding while economic rationale is often disregarded.

Aims

This paper studies CC uncertainty on productivity and profitability of European beech (Fagus sylvatica L.) and Silver fir (Abies alba Mill.). Besides, the economic consequences to actively adapt beech forests by admixing Silver fir are investigated.

Methods

We used the process-based forest growth model GOTILWA + to simulate RCP2.6, RCP4.5 and RCP8.5 climatic projection by the MPI-ESM-LR global circulation model (MPI-ESM-LR) with the CO₂ fertilization effect (eCO₂) switched on and off. We analysed the sensitivity of the land expectation value (LEV) on CC and economic parameters.

Results

CC initially increased productivity, but declined after a tipping point (2040–2070) and later also profitability (2045–2100). RCP8.5 had positive, RCP2.6 negative and RCP4.5 neutral effects on LEV. Switching off eCO₂ turned RCP8.5 from the most profitable to the least profitable scenario and the opposite for RCP2.6. CC generally reduced optimal rotation (R_opt) being scenario dependant, but comparatively more for fir than beech. Admixing fir created an economic benefit when implemented before stand age 50 of beech. This benefit was nullified with protection costs for browsing control (fencing or tree shelters).

Conclusions

Economic parameters (not CC) were the major source of uncertainty stemming from discounting factors and establishment costs. Admixture of fir and shortening rotation can provide a solution to tackle economic and climate uncertainties, but requires early admixture and browsing control.

Key message

Naturally regenerating populations of common beech, pedunculate, and sessile oaks develop strong spatial genetic structures at adult and seedling stages. Significant genetic relationship occurs between individuals growing up to 60 m apart. This indicates the minimum distance separating trees from which seeds used for reforestation should be harvested to avoid the adverse effects of excessive relatedness among offspring.

Context

Spatial genetic structure is an inherent characteristic of naturally regenerating plant populations and has practical implications in forests for the management of genetic resources.

Aims

We investigated the extent of spatial genetic structure in three broad-leaved forest tree species (common beech—Fagus sylvatica L.; pedunculate oak—Quercus robur L.; and sessile oak—Q. petraea (Matt.) Liebl.) coexisting in the same nature reserve, explored its variation among species and different life stages (adults/offspring), and tested its possible determinants.

Methods

We explored patterns of spatial distribution of individuals, and using microsatellites, we estimated parameters of spatial genetic structure based on kinship relationships, considering possible sources of variation.

Results

In adults, the strongest spatial genetic structure was found for Q. petraea (Sp = 0.0187), followed by F. sylvatica (Sp = 0.0133), and the weakest in Q. robur (Sp = 0.0080). It was uniform across different age classes in pedunculate oak but decreased with age in sessile oak. No apparent relationship between age and spatial genetic structure was found in beech. Offspring exhibited significant spatial genetic structure (ranging from 0.0122 in beech to 0.0188 in sessile oak). The cohorts of seedlings having both parents present within the study site had stronger spatial genetic structures than cohorts of seedlings with only one local parent.

Conclusion

Spatial genetic structure is strong in naturally regenerating populations of heavy-seeded forest trees. Pollen immigration from outside of a local forest stand can significantly decrease the extent of spatial genetic structure in offspring generations.

Abstract

Key message

As a result of our research, we determined that Cryptosporiopsis tarraconensis—as a new species for Central Europe—is the causative agent of leaf lesions in natural populations of hazel (Corylus avellana). Until now, this species had not been described in a natural population of C. avellana or out of the temperate climate. This is the fifth notification of this rare fungus in the world and the first from Central Europe and the natural population of the host.

Key message

This study compares the measured radial variation in wood stiffness, strength, and density of noble fir, Norway spruce, western hemlock, and western red cedar by developing mixed-effects models for each property using age as the explanatory variable. These models could be used to simulate the effect of rotation length and species choice on sawn wood properties.

Context

Timber production in Great Britain relies primarily on Sitka spruce. The use of multiple species is desirable to mitigate against biotic and abiotic risks posed to a single species. When considering alternative species, quantifying and modeling radial variation in wood properties is important to determine the potential for sawn timber production at a given rotation length.

Aims

To build empirical models for the radial variation in wood properties that can account for species.

Methods

Clear-wood samples were produced along radial transects in trees from four conifer species: Abies procera Rehder, Picea abies (L.) Karst, Tsuga heterophylla (Raf.) Sarg., Thuja plicata Donn. ex D.Don. Modulus of Elasticity, Modulus of Rupture, and density were measured on each species according to established standards. Mixed-effects models were built using ring numbers from the pith and species as explanatory variables.

Results

The same model forms could be used across the four species. Nonlinear models were developed for the Modulus of Elasticity and density. For the Modulus of Rupture, a linear model was most appropriate. The effect of species in the models was significant.

Conclusion

At similar rotation lengths, noble fir, Norway spruce, and western hemlock can produce timber with comparable properties to Sitka spruce. Overall, western red cedar would have worse properties for structural use.

Key message

J. sabina var. balkanensis, that is of hybrid origin, and its maternal progenitor J. sabina var. sabina are genetically distinct with respect to cpDNA, SNP, and SilicoDArT loci. Mostly non-overlapping distributions of the sabina and balkanensis varieties are the result of their different climatic requirements.

Context

Juniperus sabina L. is present in the Eurasian mountains, but its range is severely fragmented. In Europe, two varieties of J. sabina occur: var. sabina and var. balkanensis, the latter being an allotetraploid hybrid between the diploid var. sabina and a tetraploid ancestor of Juniperus thurifera L. The distribution of the two varieties is mostly disjunct.

Aims

Assess the taxonomic affiliation and genetic differentiation of the populations of var. sabina and var. balkanensis in Europe and Asia using cpDNA, SilicoDArT, and SNP markers. Identify climatic niches of both juniper varieties in Europe.

Methods

Altogether, 21,134 SilicoDArT, 8,579 SNP, and four cpDNA loci were used. Seven climatic variables were compared in sites inhabited by var. balkanensis and the two parental species.

Results

The SilicoDArTs and SNPs revealed a pattern of population differentiation that was congruent with the cpDNA analysis. The hybrid var. balkanensis occupies habitats with higher temperatures and intermediate levels of precipitation compared to both parental taxa.

Conclusion

The low genetic variation and significant genetic differentiation among J. sabina populations likely result from the restriction of gene flow imposed by the mountain ranges. The balkanensis variety is able to cope with hot and dry climates probably thanks to the admixture of J. thurifera genes.