Models for simulating the development of even-aged Pinus brutia stands in Middle East

Abstract

Pinus brutia occurs in the Eastern Mediterranean region and is the most widespread conifer species in Middle East. It is important for multi-purpose forestry owing to its high ecological value and economic importance. To model the stand dynamics of P. brutia, 133 semi-permanent sample plots were placed in 10 to 166 year-old stands in Syria and Lebanon, covering the whole range of variation in site quality, stand age and stand density. Site index, distance-independent diameter increment, height and self-thinning models that included country effects were fitted to the data. The site index model was fitted using the guide curve method. The data for 10-year diameter growth model consisted of past growth measurements of all trees within the 133 plots. Diameter growth was modelled using variables representing site, size and competition. The self-thinning model was developed by estimating the maximum number of trees per hectare as a function of mean diameter and site index. These are the first cross-border models in Middle East enabling forest growth and yield predictions and stand dynamics simulations on an individual-tree basis. Such models will allow, with the aid of optimization techniques, finding the optimal forest management for P. brutia forests based on different management objectives.

Intra-specific differences in allometric equations for aboveground biomass of eastern Mediterranean Pinus brutia

“…Previous research on P. brutia stand dynamics based on different and larger datasets throughout the same study area (de-Miguel et al 2010) already revealed lower dominant heights for the Lebanese stands most likely owing to both anthropogenic reasons (past forest management oriented toward selection cuttings) and environmental factors (Lebanese P. brutia forests represent the southernmost limit of the natural distribution area of this species). This suggests that the results presented in this article reflect real forest stand conditions within the study region and contribute to corroborate that tree allometry is modulated by environmental factors and forest structure in different geographic locations (Palumets 1988;Feldpausch et al 2011).…”

“…Destructive sampling is considered the most accurate method to produce reliable biomass data (Henry et al 2011). In this study, altogether 201 P. brutia trees of different sizes and shapes were felled in Syria (100 trees) and Lebanon (101 trees) beside sample plots used for growth and yield modeling by de-Miguel et al (2010de-Miguel et al ( , 2012a and by Shater et al (2011). Sample trees (Table 1) represented different growing sites, stand densities, and stand ages.…”

“…As a consequence of this, pine stands in Syria are more dense and even-aged, whereas the Lebanese stands present different degrees of "uneven agedness" resulting in higher within-stand heterogeneity in terms of tree size and shape (de-Miguel et al 2010(de-Miguel et al , 2012b. The determination of differences in stand structure based on statistical criteria such as standard deviation and skewness (Fig.…”

“…In combination with models for even-aged and unevenaged P. brutia stand dynamics (de-Miguel et al 2010(de-Miguel et al , 2012bShater et al 2011), the allometric equations provided in this study can be used to predict above-ground biomass and carbon stock under different forest management scenarios. Together with taper equations for the same species (de-Miguel et al 2012a), they can be used to assess how much carbon is sequestrated in different timber assortments.…”

“…brutia forests occurring in Syria and Lebanon constitute two non-connected populations that have been subjected to different past forest management regimes according to different forest policies, which in turn have shaped the forest stand structures ranging from mostly unthinned even-aged stands in Syria to more sparse multilayered and uneven-aged stand structures in Lebanon ( Fig. 1) (de-Miguel et al 2010(de-Miguel et al , 2012b. Since cutting of living trees is strictly forbidden in Syria, most Syrian stands are on the self-thinning limit.…”