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Variability of European beech wood density as influenced by interactions between treering growth and aspect

Forest Ecosystems 2016年第3期3卷 165-173页

作者： Daniela Diaconu Marc Wassenberg heinrich spiecker Chair of Forest Growth and Dendroecology Albert-Ludwigs-University

Background： Wood density is considered to be the most important predictor of wood quality but despite its importance, diffuse-porous tree species have been the subject of only a limited number of studies. The importance of European beech forests for Central Europe calls for profound research to examine the potential impact of a warmer climate on the quality of beech timber. Methods： In this study we analysed the influence of tree-ring width and tree-ring age on the wood density of beech, and whether the wood density response to these two parameters is modified by aspect. A linear mixed-effects model for wood density was constructed for mean density data measured with high frequency densitometry on stem discs from 72 beech trees sampled from two different aspects （northeast -NE and southwest -SW） of a valley in southwestern Germany. Results： Part of the variability of mean annual wood density was explained by cambial age： an increase in cambial age resulted in an increase in mean wood density. Tree-ring width and aspect had only a small influence on wood density, Wood density on the SW aspect was lower than on the NE with a difference of approximately 0.006 g/cm3. The between-tree variability was very high. Conclusions： The significant interaction between cambial age and aspect reflects the importance of site conditions at older tree ages： with increasing cambial age the difference between aspects becomes stronger. Our results give a better understanding of the importance of site conditions on the wood quality of beech.

关键词： Fagus sylvatica HF densitometry Wood quality Wood density Aspect

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维普期刊数据库

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Above-ground woody biomass allocation and within tree carbon and nutrient distribution of wild cherry(Prunus avium L.)-a case study

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Forest Ecosystems 2016年第2期3卷 138-152页

作者： Christopher Morhart Jonathan P. Sheppard Johanna K. Schuler heinrich spiecker Chair of Forest Growth and Dendroecology Albert-Ludwigs-University Freiburg Tennenbacher Str. 4 D 79106 Freiburg Germany

Background： The global search for new ways to sequester carbon has already reached agricultural lands. Such land constitutes a major potential carbon sink. The production of high value timber within agroforestry systems can facilitate an in-situ carbon storage function. This is followed by a potential long term ex- situ carbon sinkwithin long lasting products such as veneer and furniture. For this purpose wild cherry （Prunus avium L.） is an interesting option for middle Europe, yielding high prices on the timber market. Methods： A total number of 39 wild cherry were sampled in 2012 and 2013 to assess the leafless above ground biomass. The complete trees including stem and branches were separated into 1 cm diameter classes. Wood and bark from sub-samples were analysed separately and nutrient content was derived. Models for biomass estimation were constructed for all tree compartments. Results： The smallest diameter classes possess the highest proportion of bark due to smaller cross sectional area. Tree boles with a greater amount of stem wood above 10 cm in diameter will have a more constant bark proportion. Total branch bark proportion also remains relatively constant above *** measurements of 8 cm. A balance is evident between the production of new branches with a low diameter and high bark proportion offset by the thickening and a relative reduction in bark proportion in larger branches. The results show that a single tree with an age of 17 and 18 years can store up to 85 kg of carbon within the aboveground biomass portion, an amount that will increase as the tree matures. Branches display greater nutrient content than stem sections per volume unit which can be attributed to a greater bark proportion. Conclusions： Using the derived models the carbon and the nutrient content of above-ground woody biomass of whole trees can be calculated. Suggested values for carbon with other major and minor nutrients held within relatively immature trees strongly supports the id

关键词： Carbon sequestration Biomass Bark Branch Stem Nutrient content AIIometry Agroforestry

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维普期刊数据库

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Modelling growing space of four valuable broadleaved tree species in southern China

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Forestry Studies in China 2013年第3期15卷 167-178页

作者： Johanna SCHULER Josephine CUENI heinrich spiecker Wen-Fu GUO Faculty of Environment and Natural Resources Albert-Ludwigs-Universitt Sci-Tech Division of the Experimental Centre for Tropical Forestry Chinese Academy of Forestry

We present management tools for growing four valuable broadleaved tree species, indigenous to *** southern China. Crown diameter （CD） of the species studied can be predicted very well by using a model that is so e y a near funct on of d ameter at breast he ght （DBH）. The add t on of tree age （AGE） and yield class （YC） to this-nodel did not significantly improve its predictive capacity. We used species-specific crown diameter models to calcu- ate the amount of growing space and subsequently stand density that each species needs to achieve desired stem ＂adial growth rates. Furthermore we used this information to calculate a ＂distance factor＂, a rule of thumb that roughly ~stimates the distance between two neighboring trees needed to achieve a desired future target diameter. These tools ＇acilitate the planning of thinning regimes by using crown diameter models combined with annual radial growth rates to ;alculate the number of crop trees per hectare required to reach a desired target stem diameter.

关键词： crown diameter diameter growth growth model valuable timber management tool

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