Predicting site index of Douglas-Fir plantations from ecological variablesin the Massif Central area of France

Citation
T. Curt et al., Predicting site index of Douglas-Fir plantations from ecological variablesin the Massif Central area of France, FOREST ECOL, 149(1-3), 2001, pp. 61-74
Citations number
28
Categorie Soggetti
Plant Sciences
Journal title
FOREST ECOLOGY AND MANAGEMENT
ISSN journal
03781127 → ACNP
Volume
149
Issue
1-3
Year of publication
2001
Pages
61 - 74
Database
ISI
SICI code
0378-1127(20010801)149:1-3<61:PSIODP>2.0.ZU;2-S
Abstract
Douglas-Fir is the main species used in France for reforesting mid-elevatio n regions, mostly on former heathlands and coppices. In order to clarify it s auto-ecological Limits, and to provide forest managers with relevant info rmation for planting, we studied its productivity in a wide range of site c onditions. Based on data from 202 Douglas-Fir pure stands at mid-elevation regions, site productivity was assessed using variance analysis with site t ypes, site groups, and multiple regression analysis with ecological variabl es. Site index, determined from stem analysis data, was used as a species s pecific measure of site quality. Results show that Douglas-Fir site index i s correlated to soil nutrient status, and secondarily to soil moisture regi me. Mean stand productivity was generally high, but considerable variation in site index was determined within a study area that was classified by for est managers as uniform. Correlation between site classification and site i ndex was confirmed, because it was based on synoptic factors that are simpl e and robust indicators of site productivity. Other methods to assess site quality, such as multiple regression on ecological variables and multivaria te site groups, appear to be less explicative and robust for predicting sit e index. The results allow forest managers to predict the site index at par cel scale. Further investigation should be carried out in order to explain the major causes of the unexplained variance of site index by ecological va riables, especially genetic variation, and effect of age. (C) 2001 Elsevier Science B.V. All rights reserved.