On the use of tree‐ring area as a predictor of biomass accumulation and its climatic determinants of coffee tree growth

Abstract

The use of growth rings dimensional parameters has been an important tool for the understanding of growth, biomass allocation and climatic characterisation of forest species. However, its potential is unknown in perennial crops of socio‐economic importance, such as coffee. This work aimed to understand how the analysis of the growth rings can be used as a proxy to understand the climatic determinants of vegetative growth and biomass allocation in the different organs of coffee trees. The work was carried out in the southern region of Minas Gerais, Brazil. The structure of the growth rings of cross sections of the orthotropic stem of coffee trees (Coffea arabica L. cv. Arara) were analysed from 2011 to 2018, using standard dendrochronological techniques. Each year in that period was characterised climatically and by its bienniality. Pearson correlation statistical analysis was used for mapping the relation among annual radial growth rates of the trees and other assessed parameters as primary growth data, accumulated biomass and the climatic characteristics of the region on an annual and intra‐annual scale. During the study the water balance (conditioned by its components, Prec and ETo) and the maximum temperature were the main determinants of the characteristics of the formed ring and the plant biomass allocation. These growing characteristics were also influenced by the phenology that modulates the vegetative/reproductive growth cycles and in turn the biennial production cycles. The results show the potential of tree rings and dendrochronology as a tool that allows indirect, but long‐term, assessment of biomass allocation and growth in coffee trees.

Source‐sink patterns on coffee trees related to annual climate variability: An approach through stable isotopes analysis

“…On the other hand, considering the negative correlation between δ 13 C values and water availability (Codron et al, 2005; Ma et al, 2012; Stewart et al, 1995; Vitória et al, 2018), δ 13 C values follow the region's precipitation dynamics (data not shown in this document, but reported in Toro‐Herrera et al, 2020). 2012/2013 and 2013/2014 periods (H1 and H2) presented average annual rainfall of up to 400 mm below 2014/2015.…”

“…From the process of normalization of time series obtained from the area of the growth ring reported by Toro‐Herrera et al (2020), it was seen that there was a trend of rapid growth in the first years of the tree and later a stabilization in the following years until the date of collection. Thus, the 2012/2013 period had the highest growth rate, while the 2014/2015 period had the lowest rate.…”

“…The time series obtained from the growth ring area as a function of the time in which the rings were formed were submitted to a normalization process by the relative growth of the plant to eliminate the effect of the differences between plants. All the normalization process is found in Toro‐Herrera et al (2021), and the data obtained are shown in Supplementary Material Table 3.…”

“…These daily measurements were used to calculate monthly averages or sums of the following parameters: precipitation (Prec, in mm), evaporation (Evap, in mm), and sunlight hours (SL, in hours) calculated as the sum of daily values and minimum temperature (Tmin, in°C), maximum temperature (Tmax, in°C), relative humidity (RH, in %) and wind speed (WindS, in mps) as the average of daily values. From these parameters, other parameters such as evapotranspiration (ETo, in mm), the average maximum and minimum annual temperature (MaxTAv and MinTAv, in°C), the maximum temperature of the year (MaxTY, in°C), and the minimum temperature of the year (MinTY, in°C) were calculated according to Toro‐Herrera et al (2021).…”