Survival and growth of three endangered oak species in a Mexican montane cloud forest

Abstract

., 2017. Survival and growth of three endangered oak species in a Mexican montane cloud forest. Ann. For. Res. 60(1): 89-100.Abstract. Cloud forests are amongst the world's most impacted and endangered forest types, with Mexican cloud forests amongst the most degraded. These species rich forests are characterized by a diversity of congeneric oak species which dominate the canopy of mature forests. An improved understanding of the establishment requirements of oak seedlings in cloud forests is needed for conservation and restoration purposes. The aim of this study was to assess the influence of light conditions during early establishment of three endangered Quercus species. Seedling growth and biomass allocation in Quercus insignis M. Martens & Galeotti, Q. sartorii Liebm. and Q. xalapensis Bonpl. was determined under two light levels: light gap (1338 µmol m -2 s -1 ) and closed canopy (118 µmol m -2 s -1 ) in a cloud forest in Veracruz, Mexico. Growth and development were evaluated over the first 13 months. Results suggest there was a significant effect of light conditions on growth rate and biomass allocation. Although survival rate was similar among both environments, the three species showed lower growth rates under the closed canopy during the first nine months, while elongation rate was higher during the last three months under this environment compared to the light gap. Across all species, fresh biomass and dry biomass of roots, stem and leaves were almost 50% higher in light gap than under closed canopy. Q. insignis produced more biomass in shoots and roots than Q. sartorii and Q. xalapensis, which may increase its establishment success in shaded conditions. Results suggest that these three oak species are suited to planting in small gaps, but also in shaded understory conditions, as high early survival (>90%) may allow enrichment planting in advance of gap creation.

Seed Germination Characteristics of a Critically Endangered Evergreen Oak—Quercus marlipoensis (Fagaceae) and Their Conservation Implications

“…This result is similar to those found in other endangered Quercus spp. (e.g., Q. insignis, Q. sartorii, and Q. xalapensis) in TMCFs in Mexico, which can only grow vigorously in humid understory forests [67,68]. Rapid germination of various species of Quercus could be a strategy to reduce desiccation-induced mortality [43] and avoid predation [56].…”