首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.

Introduction  

The artificial regeneration of oaks (Quercus spp.) can supplement deficient natural regeneration, yet growth and physiology of newly planted seedlings are often negatively affected by animal herbivory. Alternative nursery stock types with improved stress resistance may help improve regeneration success.  相似文献   

2.

•Introduction   

Silviculture systems applied in Nothofagus pumilio forests are based on opening the canopy to stimulate natural regeneration by modifying light and soil moisture. The objective is to evaluate regeneration dynamics of N. pumilio along different forest canopy and solar radiation gradients.  相似文献   

3.

 Introduction   

The limited ability of Quercus species to regenerate naturally in Mediterranean forests has led to the development of various artificial regeneration methods; however, there is no general consensus as to what specific method is the best one for this purpose.  相似文献   

4.

Introduction   

Roe deer (Capreolus capreolus) browsing pressure on vegetative regeneration of Turkey oak (Quercus cerris) and chestnut (Castanea sativa) and roe deer use of coppiced areas were investigated.  相似文献   

5.

• Introduction   

Shrubs are recognized as important tree regeneration niches. In this study, we experimentally analysed the effects of shrub presence, canopy cover (closed cover and open cover-gaps), and seedling size on Pinus pinaster growth.  相似文献   

6.

Introduction   

The great spatial and temporal heterogeneity of Mediterranean ecosystems can influence establishment success in woody species, whose natural regeneration occurs to a very small extent. In this work, the effect of the spatial pattern of environmental variables (light availability, soil moisture and herbaceous production) on seedling emergence, growth, survival and establishment success was examined by using a spatially explicit approach.  相似文献   

7.

? Key message

Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density.

? Context

Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in low-elevation mountain forests.

? Aims

We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abies regeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies.

? Methods

The study was conducted in the Sto?owe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m2) for natural regeneration, light availability, soil pH, and understory vegetation assessment.

? Results

The highest densities of natural regeneration of P. abies were observed in sites with moderate light availability (0.1–0.2 of open sky) and low pH (3.5–4.5), and located relatively far from the riverbank. Cover of 22 understory plant species were correlated with natural P. abies regeneration densities, mostly positively.

? Conclusion

Different stages of natural regeneration of P. abies revealed different regeneration niches. Most understory plant species (bryophytes and herbs typical of coniferous forests) do not compete with natural regeneration of P. abies.
  相似文献   

8.

• Introduction   

Canopy gap dynamics in old-growth boreal forests is a result of tree mortality caused by insects, diseases, or meteorological phenomena. Canopy gaps improve the possibilities of natural regeneration, and concentrations of decomposed deadwood are often found in these natural openings, which provide specific habitats for many deadwood-dependent species and organisms.  相似文献   

9.

Key message

Natural regeneration patterns of conifer species were studied. Seedling regeneration follows patterns responding to stand structure and site condition factors along shade and drought tolerance gradients. Our findings can assist in adaptive forest management for maintaining sustainable regeneration and plant biodiversity.

Context

Seedling regeneration can vary with stand factors of overstory trees and understory non-tree vegetation and site conditions.

Aims

Natural seedling regeneration patterns of coniferous species were investigated using Forest Inventory and Analysis (FIA) data of 10 common species across the Inland Northwest, USA.

Methods

Zero-inflated negative binomial models were developed to understand the responses of natural regeneration to stand factors and site conditions.

Results

Seedling occurrence varies along shade and drought tolerance gradients responding to stand structure and site conditions. Two moderate shade-tolerant species of different drought tolerance contributed as a transition. Strong response patterns were revealed for seedling density, in which seedling density was improved with the presence of conspecific trees while limited by competition, especially from the understory vegetation layer.

Conclusion

Overstory structure and understory vegetation could improve or hinder natural regeneration of coniferous tree species given different shade tolerance and site conditions. Our findings can be effectively implemented in adaptive forest management for maintaining sustainable regeneration of specific conifers in broad temperate mixed forests.
  相似文献   

10.

Key message

In Abies alba Mill. stands and mixed stands of A. alba and Picea abies L. (H. Karst), microsites neighbouring the trunks of adult trees were more conducive to A. alba regeneration. Although at the stand level, the effect of Fagus sylvatica L. was positive; the local effect of the adult F. sylvatica neighbourhood was insignificant. Hence, forming mixed stands with a fine-grained mosaic of admixed species might better facilitate natural regeneration of A. alba than monospecific stands.

Context

The establishment of natural regeneration in Abies alba Mill. stands is a slow, spatially heterogeneous and stochastic process. Recent studies based on inventory data indicate that A. alba more readily regenerates in mixed stands than in monospecific stands.

Aims

The objective was to examine how this positive association evidenced at the stand level operates on the scale of microsites with contrasting local species composition and stand density.

Methods

In 8 monospecific and 22 mixed stands with Fagus sylvatica L. or Picea abies L. (H. Karst), microsites with a contrasting density of A. alba seedlings were selected and compared in terms of local species composition, stand density, canopy characteristics and topsoil properties.

Results

In A. alba stands, seedling density was positively associated with the proximity of adult trees. In mixed stands of A. alba and P. abies, adult trees of both species exerted a positive effect on A. alba regeneration, but the P. abies neighbourhood influenced regeneration occurrence more strongly than the A. abies neighbourhood. In mixtures with F. sylvatica, however, the effect of local stand density and local species composition was not evidenced at all.

Conclusion

Although at the stand level, P. abies and F. sylvatica exert a positive effect on A. alba regeneration, on the microsite scale, their influences differ. In stands with a dominance of A. alba, the hampered seedling establishment in gaps may be considered an inhibitive effect that facilitates the emergence of other species.
  相似文献   

11.

Introduction   

Wood quality is an important criterion in the selection of superior genotypes when breeding for solid wood.  相似文献   

12.

? Context

Understanding the biological mechanisms related to plant response to disturbance is essential for predicting the changes in the structure of plant communities resulting from disturbance.

? Aims

The aims of this study are to identify the regeneration traits linked to the response to disturbance of tree species of a montane cloud forest in order to define regeneration types and to explore whether disturbance intensity acts to select specific regeneration types that can colonize disturbed plots.

? Methods

A theoretical model was developed and evaluated using structural equation modeling to link two latent variables: regeneration type and vulnerability to disturbance. We studied two plots that were subjected to different intensities of disturbance and one plot of mature forest.

? Results

Shade tolerance, dispersal mode, and the capacity to form a seed bank were the traits that determine regeneration type. There was a trend for re-sprouting capacity to be associated with the regeneration types dominant in disturbed plots. Regeneration types were differentially distributed among the sites.

? Conclusion

There was evidence that disturbance intensity has a filtering effect on the colonization of disturbed plots. Species vulnerability to disturbance depends on specific combinations of regeneration traits. Structural equation modeling is useful for exploring plant response to disturbance using key parameters linked to plant persistence.  相似文献   

13.
14.

Context

This study investigates post-fire natural regeneration of Aleppo pine (Pinus halepensis) forests at Ilia region (Peloponnesus, Greece) following the catastrophic fire of 2007.

Aims

The objective of this study is the prediction of P. halepensis post-fire regeneration at a regional scale through an integrated geographic information systems (GIS) model as a basis for post-fire management plans.

Methods

The model was developed in three interconnected stages: (1) field data collection, (2) development of two prediction models (based on interpolation of field data and multi-criteria evaluation (MCE) that combined factors known to affect regeneration), and (3) combination of applied models using Bayesian statistics.

Results

Post-fire pine regeneration presented high variation among the studied plots. Redundancy analysis revealed the positive effect of fallen branches and a negative correlation with altitude. Both modeling approaches (geostatistical and MCE) predicted the post-fire pine regeneration with high accuracy. A very significant correlation (r?=?0.834, p?<?0.01) was found between the combined final model and the actual number of counted seedlings, illustrating that less than 10?% of the studied area corresponds to sites of very low post-fire pine regeneration.

Conclusions

The combination of GIS models increased the prediction success of different levels of pine regeneration. Low-altitude areas with low grass cover overlying tertiary deposits were proved the most suitable for pine regeneration, while stands developing on limestone proved least suitable. The proposed methodology provides management authorities with a sound tool to quickly assess Aleppo pine post-fire regeneration potential.  相似文献   

15.

Objective  

Knowledge of mechanisms determining plant persistence in range edges is essential because peripheral populations face increasing risk and they often maintain unique genotypes.  相似文献   

16.

• Background   

Tree breeders have been reluctant to include wood traits in tree improvement programs owing to logistic difficulties and the cost associated with the assessing the traits.  相似文献   

17.
18.

• Introduction   

One current explanation for worldwide drought-induced tree mortality states that reduced photosynthesis and continued respiration lead to carbon depletion and eventually to carbon starvation.  相似文献   

19.

• Introduction  

The study of phenotypic and genetic differentiation between incipient species or species that have recently diverged provides insights into the evolutionary history of species complexes and may contribute to our understanding of how species will evolve in contrasting environmental conditions.  相似文献   

20.

Context  

The European black poplar (Populus nigra) is considered one of the most seriously endangered indigenous tree species. However, the total area covered by monoclonal plantations of hybrid poplar is growing, because of the high profitability of these trees.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号