Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obta...Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country-and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition.Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from10% to 53% depending on the species. Variables related to forest structure(basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species.Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etc.展开更多
There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limi...There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limited by the lack of accurate long-term monitoring in multi-age mixed native forests to provide estimates of both expected mean diameter increments and the statistical variation in those estimates. A dataset from Eucalyptus-dominated native forests in subtropical Queensland, Australia offers an opportunity to provide accurate estimates of tree and forest growth rates. Over 86,400 trees from 155 native species were identified and remeasured between 1936 and 2011 in 641 permanent sample plots across a 500-2000 mm mean annual rainfall gradient. Individual tree diameter at breast height （DBH） increments observed for all species ranged mainly from 0.01 to 0.5 cm yr-1 （94 % of values）, with consistentdifferences between rainfall zones （mean of 500- 2000 mm yr-1）, and varying differences between species （155） and stem diameter class （10-100 cm）. For some spe- cies, diameter increment increased progressively with rain- fall （e.g. Eucalyptus siderophloia, Eucalyptus propinqua, and Lophostemon confertus）, but in others （e.g. Corymbia citriodora subsp, variegata, Corymbia intermedia, and Eucalyptus biturbinata） the greatest diameter increments were recorded between 1200 and 1600 mm yr-1. Where there were sufficient data, most species exhibited a quadratic relationship between DBH increment and DBH class, but two species （ Callitris glaucophylla and Eucalyptus crebra） native to the 500-800 mm annual rainfall zone showed lin- ear increases in DBH increment with increasing DBH. Continued monitoring of these plots would add to their already great value.展开更多
The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn ma...The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn mass of pedunculate oak during 2010 in the absence of drought stress and during 2011 under the impact of moderate drought stress.According to the results,moderate drought stress significantly reduced net photo synthetic rate,stem diameter increment and height growth increment,while acorn mass was not affected.Suboptimal nitrogen nutrition significantly reduced the net photo synthetic rate and stem diameter increment only in the wet year,acorn mass in both wet and dry years,while height growth increment was not significantly reduced by suboptimal nitrogen nutrition in either year.The results indicate that optimal nitrogen levels can stimulate photo synthetic rate and stem diameter increment of pedunculate oak only in the absence of moderate drought stress.Moreover,the results show that moderate drought stress is a more dominant stressor for photosynthesis and growth of pedunculate oak than suboptimal nitrogen nutrition,while for acorn development,it is the more dominant stressor.展开更多
We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in sout...We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in southern Turkey.PCT was set up using a randomized complete block design with three replicates and three treatments(control,2–2.5 m×–2.5 m and 3–3.5 m×–3.5 m spacing).The experimental plots were established in March 2014.At the end of the growing seasons for three years(2014–2016),growth parameters such as diameter,height and crown radius were measured.PCT was found to be significantly effective on diameter,height,individual tree basal area,and crown radius increment at the end of the third year(p<0.05).While diameter,individual tree basal area and crown radius increment increased with increasing PCT intensity,height increment was higher in control than PCT.Although the PCT treatments applied with 3–3.5 m spacing affected individual tree development positively,we need long-term results on wood quality and yield.According to the short-term results,it is thought that it is better to lower the stand closeness gradually,so,it may be advisable to apply PCT by 2–2.5 m×–2.5 m spacing.展开更多
Bio-energy and biomass system is a new scientific field, very interesting, where there can find new available information; however, there is also place for other novelties. A lot of projects and experiences regarding ...Bio-energy and biomass system is a new scientific field, very interesting, where there can find new available information; however, there is also place for other novelties. A lot of projects and experiences regarding to what mentioned above, lead to the credence that forest biomass assume a fundamental role, inasmuch they constitute a renewable resource, already or easily present, in the environment. The main purpose of undertaking this study is to analyse the obtainable biomass yields from black locust （Robinia pseudoacacia L.） SRF. Four different plantations have been situated on lands of different fertilities in Italy and Albania. Neither irrigation nor fertilization has been applied. Two different methodologies of biennial harvesting have been compared on black locust plantation situated in Italy. The first one is the contemporary cutting and chipping, while the second with cutting, field seasoning of trees and then chipping. In Albania the analyses of planted trees were mainly focused on height and diameter growth. They revealed a good continuation which means that the bed conditions of abandoned terrain, and climate considering the extended drought period of last summer, don＇t affect the growth.展开更多
基金funded by the SIMWOOD project(Grant Agreement No.613762)of the EU H2020 Programmefacilitated by the Alter For project(Grant Agreement No.676754)+3 种基金the VERIFY project(Grant Agreement No.776810)Co-funding was received from the topsector Agri&Food under No.AF-EU-15002The Dutch National Forest Inventory is funded by the Ministry of Economic AffairsThe regional forest inventory in Piemonte was produced with the support of EU structural funds
文摘Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country-and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition.Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from10% to 53% depending on the species. Variables related to forest structure(basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species.Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etc.
文摘There is widespread interest in estimating and forecasting individual tree and forest growth rates for restoration and carbon sequestration objectives. Outside intensively managed forests, past attempts have been limited by the lack of accurate long-term monitoring in multi-age mixed native forests to provide estimates of both expected mean diameter increments and the statistical variation in those estimates. A dataset from Eucalyptus-dominated native forests in subtropical Queensland, Australia offers an opportunity to provide accurate estimates of tree and forest growth rates. Over 86,400 trees from 155 native species were identified and remeasured between 1936 and 2011 in 641 permanent sample plots across a 500-2000 mm mean annual rainfall gradient. Individual tree diameter at breast height （DBH） increments observed for all species ranged mainly from 0.01 to 0.5 cm yr-1 （94 % of values）, with consistentdifferences between rainfall zones （mean of 500- 2000 mm yr-1）, and varying differences between species （155） and stem diameter class （10-100 cm）. For some spe- cies, diameter increment increased progressively with rain- fall （e.g. Eucalyptus siderophloia, Eucalyptus propinqua, and Lophostemon confertus）, but in others （e.g. Corymbia citriodora subsp, variegata, Corymbia intermedia, and Eucalyptus biturbinata） the greatest diameter increments were recorded between 1200 and 1600 mm yr-1. Where there were sufficient data, most species exhibited a quadratic relationship between DBH increment and DBH class, but two species （ Callitris glaucophylla and Eucalyptus crebra） native to the 500-800 mm annual rainfall zone showed lin- ear increases in DBH increment with increasing DBH. Continued monitoring of these plots would add to their already great value.
基金conducted as part of the research project“Reproductive physiology of pedunculate oak(Quercus robur L.)in Spa?va”fully supported and funded by“Croatian Forests Ltd”。
文摘The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn mass of pedunculate oak during 2010 in the absence of drought stress and during 2011 under the impact of moderate drought stress.According to the results,moderate drought stress significantly reduced net photo synthetic rate,stem diameter increment and height growth increment,while acorn mass was not affected.Suboptimal nitrogen nutrition significantly reduced the net photo synthetic rate and stem diameter increment only in the wet year,acorn mass in both wet and dry years,while height growth increment was not significantly reduced by suboptimal nitrogen nutrition in either year.The results indicate that optimal nitrogen levels can stimulate photo synthetic rate and stem diameter increment of pedunculate oak only in the absence of moderate drought stress.Moreover,the results show that moderate drought stress is a more dominant stressor for photosynthesis and growth of pedunculate oak than suboptimal nitrogen nutrition,while for acorn development,it is the more dominant stressor.
基金This study was a part of the doctoral dissertation and supported by Suleyman Demirel University Projects(Project numbers:OYP-05241-DR14 and 4167-OYP-D2-14).
文摘We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in southern Turkey.PCT was set up using a randomized complete block design with three replicates and three treatments(control,2–2.5 m×–2.5 m and 3–3.5 m×–3.5 m spacing).The experimental plots were established in March 2014.At the end of the growing seasons for three years(2014–2016),growth parameters such as diameter,height and crown radius were measured.PCT was found to be significantly effective on diameter,height,individual tree basal area,and crown radius increment at the end of the third year(p<0.05).While diameter,individual tree basal area and crown radius increment increased with increasing PCT intensity,height increment was higher in control than PCT.Although the PCT treatments applied with 3–3.5 m spacing affected individual tree development positively,we need long-term results on wood quality and yield.According to the short-term results,it is thought that it is better to lower the stand closeness gradually,so,it may be advisable to apply PCT by 2–2.5 m×–2.5 m spacing.
文摘Bio-energy and biomass system is a new scientific field, very interesting, where there can find new available information; however, there is also place for other novelties. A lot of projects and experiences regarding to what mentioned above, lead to the credence that forest biomass assume a fundamental role, inasmuch they constitute a renewable resource, already or easily present, in the environment. The main purpose of undertaking this study is to analyse the obtainable biomass yields from black locust （Robinia pseudoacacia L.） SRF. Four different plantations have been situated on lands of different fertilities in Italy and Albania. Neither irrigation nor fertilization has been applied. Two different methodologies of biennial harvesting have been compared on black locust plantation situated in Italy. The first one is the contemporary cutting and chipping, while the second with cutting, field seasoning of trees and then chipping. In Albania the analyses of planted trees were mainly focused on height and diameter growth. They revealed a good continuation which means that the bed conditions of abandoned terrain, and climate considering the extended drought period of last summer, don＇t affect the growth.
