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Species-specific,pan-European diameter increment models based on data of 2.3 million trees

Forest Ecosystems 2018年第3期5卷 277-295页

作者： Mart-Jan Schelhaas Geerten M Hengeveld Nanny Heidema Esther Thurig Brigitte Rohner Giorgio Vacchiano Jordi Vayreda John Redmond Jaroslaw Socha Jonas Fridman Stein Tomter Heino Polley Susana Barreiro Gert-Jan Nabuurs Wageningen University and Research Wageningen Environmental Research(WENR)Droevendaalsesteeg 36708PB WageningenThe Netherlands Wageningen University and Research BiometrisDroevendaalsesteeg 16708PB WageningenThe Netherlands Wageningen University and Research Forest and Nature Conservation Policy GroupDroevendaalsesteeg 36708PB WageningenThe Netherlands Swiss Federal Institute for Forest Snow and Landscape Research WSLResource AnalysisZuercherstrasse 111CH-8903 BirmensdorfSwitzerland European Commission Joint Research CentreDirectorate DSustainable Resources-Bio-Economy UnitIspraItaly CREAF 08193 Cerdanyola del VallesSpain Univ Autonoma Barcelona 08193 Cerdanyola del VallesSpain Forest Service Department of AgricultureFood and the MarineJohnstown Castle EstateCo.WexfordIreland Department of Biometry and Forest Productivity Institute of Forest Resources ManagementFaculty of ForestryUniversity of Agriculture in KrakowAI.29Listopada 4631-425CracowPoland Swedish University of Agricultural Sciences (SLU) 90183 UmeaSweden Norwegian Institute of Bioeconomy Research P.O.Box 115N-143 1AsNorway Thunen Institute Institute of Forest EcosystemsAlfred-Mo1ler-Strabe 1Haus41/4216225 EberswaldeGermany Forest Research Centre (CEF) Instituto Superior de AgronomiaUniversidade de LisboaTapada da Ajuda1349-017Lisbon.Portugal Wageningen University and Research Forest Ecology and Forest Management GroupDroevendaalsesteeg 36708PBWageningenThe Netherlands

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 ***: 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 ***: 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 ge

关键词： European forests Diameter increment model Climate change growth modelling National forest inventory

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Site index for teak in Colombia

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Journal of Forestry Research 2012年第3期23卷 405-411页

作者： Danny A.Torres Jorge I.del Valle Guillermo Restrepo Office National de Forêts International 2av.de Saint-Mandé75570 Paris Cedex 12France Universidad Nacional de Colombia sede Medellín Apartado Aéreo 568MedellínColombia Independent consultant

Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations. Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and clas- sify site quality ofteak （Tectona grandis） plantations by using data from 44 permanent sample plots established since 1990 in 3--22 years old teak plantations in the Colombian Caribbean region. We used Korf＇s and yon Bertalanffy＇s models to fit curves as non-linear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf＇s model was superior. The resulting curves were anamorphic and closely reflected high variability in site quality. Five site classes were clarified： at a base age of 12 years old, teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m in the worst sites, and in the averages sites, 15.8-18.8 m. Using this model, we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.

关键词： Tectona grandis site index growth modelling permanentsample plots Colombia

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Evaluation of unconstrained and constrained mathematical functions to model girth growth of rubber trees (Hevea brasiliensis) using young agemeasurements

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Journal of Forestry Research 2012年第3期23卷 365-375页

作者： T.R.Chandrasekhar Rubber Research Institute of India Hevea Breeding Sub StationKadaba-574221DK DistrictKarnatakaIndia

No attempt has been made to date to model growth in girth of rubber tree （Hevea brasiliansis）. We evaluated the few widely used growth functions to identify the most parsimonious and biologically reasonable model for describing the girth growth of young rubber trees based on an incomplete set of young age measurements. Monthly data for girth of immature trees （age 2 to 12 yearsi from two locations were sub- jected to modelling. Re-parameterized, unconstrained and constrained growth functions,of Richards （RM）, Gompertz （GM） and the monomo- lecular ＇model ^（MM） were fitted to data. Duration of growth was the firsf constraint introduced. In the stagel We attempted a population aver- age （PA） model to capture the trend in growth. The best PA model was fitted as a subject specific （SS） model. We used appropriate error vari- ance-covariance structure to account for correlation due to repeated measurements over time. Unconstrainecl functions underestimated the asymptotic maximum that did not reflective carrying capacity of the locations. Underestimafions were attributed to the partial set＇ of meas- urements made during the early growth phase of the trees. MM proved superior to RM and GM. In the randomcoefficient models, both Gf and Go appeared to be influenced by tree level effects. Inclusion of diagonal definite positive matrix removed the correlation between random effects. The results were similar at both locations. In the overall assessment MM appeared as the candidate model for studying the girth-age relationships in Hevea trees. Based on the fitted model we conclude that, in Hevea trees, growth rate is maintained at maximum value at to, then decreases until the final state at dG/dt 〉 0, resulting in yield curve with no period of accelerating growth. One physiological explanation is that photosynthetic activity in Hevea trees decreases as girth increases and constructive metabolism is larger than destructive metabolism.

关键词： natural rubber Hevea Brasiliensis growth modelling un-constrained functions constrained functions mixed model

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