Patterns of growth, recruitment, mortality and biomass across an altitudinal gradient in a neotropical montane forest, Dominican Republic

We examined stand dynamics and biomass along an altitudinal gradient in a tropical montane forest (TMF) in the disturbance-prone Cordillera Central, Dominican Republic. We tested the general hypothesis that chronic disturbance by fire, wind, floods and landslides results in a landscape of relatively low above-ground biomass with high rates of mortality, recruitment and growth as compared with other TMFs. We also expected above-ground biomass to decrease with altitude in part due to declines in growth and increased biomass losses from mortality with increasing altitude. We resurveyed 75 0.1-ha plots distributed across the altitudinal gradient (1100–3100 m asl) 8 y after they were established. Our observations provided mixed evidence on these hypotheses. Turnover rates were high (>2% y−1) and significantly greater on windward slopes. Above-ground biomass (mean = 306 Mg ha−1, 95% CI = 193–456 Mg ha−1) was highly variable but comparable to other TMFs. Altitudinal patterns of declining biomass and above-ground growth matched observations for other TMFs, whereas mortality and recruitment exhibited no altitudinal trends. More quantitative studies in a variety of TMF settings are needed to better understand how natural disturbance, complex environmental gradients and species dynamics interact to regulate carbon storage, sequestration and turnover across altitudinal gradients in TMFs.