A Semi-empirical Approach Based on Genetic Programming for the Study of Biophysical Controls on Diameter-Growth of Fagus orientalis in Northern Iran

Abstract

This paper examines the possible ecological controls on the diameter increment of oriental beech (Fagus orientalis Lipsky) in a high altitude forest in northern Iran. The main objectives of the study are computer-generated abiotic surfaces and associated plot estimates of (i) growing-season-cumulated potential solar radiation, (ii) seasonal air temperature, (iii) topographic wetness index in representing soil water distribution, and (iv) wind velocity generated from the simulation of fluid-flow dynamics in complex terrain. Plot estimates of the tree growth are based on averaged plot measurements of diameter at breast height increment during a growing period of nine years (2003–2012). Biotic variables related to the tree diameter increment involve averaged 2003 tree diameter and basal area measured in individual forest plots. In the modelling data (144 plots), the assemblage of modelled and observed site variables explained 75% of the variance in plot-level diameter increment. In the validation data (32 plots), the degree of explained variance was 77%. Mean tree diameter at breast height showed the strongest correlation with diameter increment, explaining 32% of the variation between-plot, followed by the configuration of topography and re-distribution of surface water (19.5%) and plot basal area (16.9%). On average, localised estimates of solar radiation and wind velocity potentially contribute to about 20% of the control on plot-level mean increment in oriental beech of the area. The results of the genetic programming showed that controlling the stand basal area and tree size by thinning and/or selective harvesting can have a favourable impact on the future distribution of mean diameter in oriental beech.

Estimation of Tree Heights in an Uneven-Aged, Mixed Forest in Northern Iran Using Artificial Intelligence and Empirical Models

“…The use of artificial intelligence techniques for forestry issues has become more and more popular recently, but is often limited to ANNs; other techniques such as ANFIS and fuzzy logic also have great potential for many forest modeling [13,56]. A t-test was performed to compare the results of R 2 and RMSE, and according to our results (p ≥ 0.005), there was no significant difference between the accuracies of ANN and ANFIS models in estimating tree heights in the study area.…”

A Combination of Biotic and Abiotic Factors and Diversity Determine Productivity in Natural Deciduous Forests

“…This method is used in many fields of engineering, forestry, agriculture, etc. [33]. This model is able to accommodate three-dimensional Navier-Stokes equations, which include thermal processes and the effect of atmospheric turbulence [46,47].…”

“…However, soil water requirements and tolerances vary by tree species. Wind was assumed an important and influential nonbiological factor in plant production [32,33]. Wind speed exerts both positive and negative physiological and biomechanical effects on plants.…”

Structural and functional improvement of urban fringe areas: toward achieving sustainable built–natural environment interactions

“…The concept of ecosystem services brings up the function of the natural systems and their interconnected elements into the play as opposed to purely conserving these assets (De Groot et al 2002;Lafortezza et al 2013). The importance of these elements as primary integrated components of urban ecosystems is increasing and providing a large number of functions such as health functions (Nutsford et al 2016;Saeedi and Darabi 2015; social functions (Benedict and McMahon 2000;Goodarzi et al 2016a, b), ecological functions (Akhzari et al 2015;Darabi and Saeedi 2013) and economic importance (Bayat et al 2019;Bourque and Bayat 2015;Lange et al 2008). Thus, considering the role of these features in the structure and function of cities, especially in semiarid cities like Tehran, is crucial.…”