Semideciduous Seasonal Forest Production of Leaves and Deciduousness in Function of the Water Balance, LAI, and NDVI

Abstract

This study investigated the relationship between leaf production, litterfall, water balance, Leaf Area Index (LAI), and Normalized Difference Vegetation Index (NDVI) in semideciduous forests. The goal was to model this phenomenon to obtain the estimates of this component as an additional compartment of the ecosystem carbon sink. The tests were conducted in eight semideciduous forest fragments. Twenty-four permanent plots were monitored monthly and LAI measurements and weighing of litterfall deposited in nets were conducted for a period of thirteen months. In this period, Landsat 5 and IRS satellite images were obtained and processed for generation of NDVI. The water balance was calculated for each day. The relationship among the variables “leaf dry weight,” “LAI,” “NDVI,” and “water balance” was verified and a regression model was built and evaluated. The deciduous phenomenon can be explained by hydric balance, and LAI and NDVI are ancillary variables. The tendency of the variables in the period of 13 months was explained by quadratic functions. The varied behavior among the monitoring sites helped to know differences in the deposition of leaves. This study showed that only the leaf component of the litterfall of a semideciduous forest in tropical climate can capture 4 to 8 Mg·ha−1·yr−1of CO2and this amount can be estimated using climate, biophysics, and vegetation index variables.

Nutritional Contribution Model of Litterfall for Adjacent Areas According to the Distance of Forest

“…In order to calculate the daily water excess and the water deficiency, an available water capacity of 150 mm was used and the methodology described by Pereira, A. R., et al [28] was carried out by the development of a VBA (Visual Basic for Application) routine [13]. The data were summed for the periods of leaves collecting in each area.…”

“…This phenomenon can be associated with a second-degree polynomial model. With this model, using data of 2011/2012 [13], it recorded a minimum point between the end of February and the beginning of March. The September was the period with more fall of leaves.…”

“…The amount of plant material deposited from forest ecosystems forming the litterfall is expressive, and reaches tons per hectare per year [7,[13][14][15][16][17][18]. The rate of litterfall is considered all the material deposited on the soil surface of a forest in a given period, which can be measured by deposition in collectors of pre-set sizes per unit time [19].…”

Forest Patch Conservation Indicators

“…The methodological procedure is described by Costa et al (2014). The LAI was measured per plot, then the average annual value per site was calculated, LAImd_anual (m 2 of leaves.m -2 of land).…”

Nutritional Contribution of Litterfall for a Surrounding Forest Area according to the Distance of a Forest Fragment

“…The amount of plant material deposited from forest ecosystems forming the litterfall is expressive, and reaches tonnes per hectare per year (Costa et al, 2014;Giacomo et al, 2012;Gomes et al, 2010;Silva et al, 2007;Vital et al, 2004;Figueiredo Filho et al, 2003). The rate of litterfall is considered all the material deposited on the soil surface of a forest in a given period, which can be measured by deposition in collectors of pre-set sizes per unit time (Poggiani and Schumacher, 2000).…”