Abstract

CASTRUITA-ESPARZA, Luis U. et al. Basal area increment series of dominant trees of Pseudotsuga menziesii (Mirb.) Franco show periodicity according to global climate patterns. Rev. Chapingo ser. cienc. for. ambient [online]. 2016, vol.22, n.3, pp.379-397. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2015.10.048.

Tree species like Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) are sensitive to climate cycles and show well defined growth rings. The careful selection of dominant trees with circular Ttrunk section allow the analysis of tree growth trajectories. In this study, we used direct measurements of basal area increment (BAI) to explain biological periodicity and forecast basal area growth of Douglas-fir growing in Western Mexico. To remove the age effect on tree growth we also ran the analysis in terms of cambial age. Results showed significant (P < 0.05) correlation between BAI and precipitation from January to July. We found periodicities in tree growth of 7, 21, 27 and 60 years. However, the 60-year period, was determinant to build an ARIMA model (0,1,1), to forecast BAI for the next decades. Tree growth projections suggest reduced BAI in mature dominant trees for the next decades. Decreased tree-growth is an unexpected result, as BAI in dominant trees remains constant up to the biological age. Our finding is concurrent with a general decrement in tree growth in other forests of the world due to water stress, which suggests that the future climatic variability may worsen health conditions of Douglas-fir forests in North Mexico.

Keywords : Dendrochronology; tree-ring; forest productivity; temperate forests; time series analysis.