Individual distance-independent girth increment model for Douglas-fir in southern Belgium
نویسندگان
چکیده
An individual distance-independent girth increment model for pure stands of Douglas-fir (Pseudotsuga menziesii (MIRB.) FRANCO), comprising two equations, is presented. The data used to fit the model were collected from 1007 trees in 42 plots installed in regularly stocked and even-aged stands located in Wallonia (southern Belgium). Both equations predict girth increment from individual girth, dominant height, basal area per hectare, stand mean girth and variables linked to site fertility. These last variables are the site index H50 in the first equation, and a combination of mean annual rainfall and altitude in the second. The coefficient of determination ranges from 0.434 to 0.481 and the root mean square error ranges from 0.7857 to 0.8194 cm year. Estimated increments of 224 Douglas-fir trees in 12 different and independent stands were used to validate the model, which is expected to provide reliable predictions for most of the pure Douglas-fir stands located in the study area.
منابع مشابه
Thinning Mixed-Species Stands of Douglas-Fir and Western Hemlock in the Presence of Swiss Needle Cast: Guidelines Based on Relative Basal Area Growth of Individual Trees
37 In coastal forests of the Pacific Northwest, young coniferous plantations typically contain a 38 mixture of planted and natural Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga 39 heterophylla). Swiss needle cast (SNC) disease inhibits the growth of Douglas-fir to varying 40 degrees in these stands, depending on SNC severity. In addition to the value differential between 41 Dou...
متن کاملMovement and Persistence of Chloropicrin, Vapam, and Methylisothiocyanate in Untreated Southern Pine and Douglas-Fir Timbers
Methylisothiocyanate The fumigants were introduced into 2.54-cm-diameter holes at timber midlength. Fumigants diffused throughout the cross-sectional area of both southern pine and Douglas-fir. The brownand white-rot fungi generally showed similar tolerance to the fumigants. Chloropicrin killed most fungal cultures in both tim bers 0.30 in from the treatment centerline (CL) within 1 week after...
متن کاملSpatiotemporal Patterns of Ring-width Variability in the Northern Interior West
A fundamental goal of forest biogeography is to understand the factors that drive spatiotemporal variability in forest growth across large areas (e.g., states or regions). The ancillary collection of increment cores as part of the IW FIA Program represents an important non-traditional role for the development of unprecedented data sets. Individual-tree growth data from increment cores were pair...
متن کاملDevelopment of a Hybrid Modeling Framework for Intensively Managed Douglas-Fir Plantations in the Pacific Northwest.
approved: Douglas A. Maguire Forest growth models in the Pacific Northwest are predominantly empirical. Predictions of yield under alternative silvicultural regimes cannot rely completely on field trials; yet empirical growth models are often inadequate for extrapolating untested regimes and genotypes. The limitations of current models include (1) long time-steps (e.g. 5-10 years); (2) insuffic...
متن کاملMaturation in Douglas-fir: II. Maturation characteristics of genetically matched Douglas-fir seedlings, rooted cuttings and tissue culture plantlets during and after 5 years of field growth.
Seedlings, rooted cuttings from juvenile stock plants, and cotyledon-derived tissue culture plantlets were propagated from several coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) full-sib families so that the rooted cuttings and plantlets were clonally identical. The stock types (seedlings, rooted cuttings and plantlets) were planted in the field in spring 1987. In fall 1991, after f...
متن کامل