Ecofunctional traits and biomass production in leguminous tree species under fertilization treatments during forest restoration in Amazonia

Background: Choosing the correct species and fertilization treatments is a determining factor in the success of forest restoration. Methods: A field study was conducted in a degraded area near the Balbina hydroelectric dam in Amazonas State (AM), Brazil, to evaluate two hypotheses: (i) leguminous tree species exhibit differences in growth, leaf nutrient content, and photosynthetic nutrient use efficiencies; and (ii) differences in these characteristics depend on the fertilization treatments to which the species have been subjected. Dipteryx odorata, Inga edulis and Schizolobium amazonicum were subjected to the following treatments: (T1) unfertilized control; (T2) post-planting chemical fertilization; (T3) post-planting organic fertilization and (T4) combined chemical and organic post-planting fertilization. Results: In general, I. edulis had the highest absolute growth rate of biomass under all of the fertilization treatments. I. edulis and S. amazonicum showed the highest growth rates under the T4 treatment. D. odorata showed the greatest responses under the T2 and T4 treatments. Native leguminous trees with higher photosynthetic performance and better nutrient use efficiency exhibited greater growth and biomass production. Conclusion: The results suggest that an adequate balance between leguminous species selection and fertilization will aid in the success of forest restoration in Amazonia. © 2016 by the authors

Measuring the impact of flooding on Amazonian trees: Photosynthetic response models for ten species flooded by hydroelectric dams

Increasing areas of Amazonian forest are coming under flood stress due to dam construction and greater variability in river flood levels due to climate change. The physiological responses of Amazonian trees subjected to flooding are important to understand the consequences of these changes. Irradiance response curves for photosynthesis obtained from ten tropical tree species growing in flooded areas were used to fit three empirical models. The study was done in floodplains along the Uatumã River, both upstream and downstream of the Balbina Hydroelectric Dam in Brazil's state of Amazonas (01°55′S; 59°28′W). Ten species were studied. Models compared were: non-rectangular hyperbola, rectangular hyperbola, and exponential. All models were quantitatively adequate for fitting the response of measured data on photosynthesis to irradiance for all ten species in the non-flooding and flooding periods. Considerable variation was found among the model estimates of maximum photosynthesis (Pnmax), dark respiration (Rd) and apparent quantum yield of photosynthesis (α). For photosynthesis, the two hyperbolas overestimated Pnmax while EXP presented more realistic values. For estimating Rd, RH presented the most realistic values. To avoid unrealistic value estimates of Rd, we recommend adding measured Rd values to the regressions. The results suggest that the EXP model presented the most realistic Pnmax and α values, and, in spite of less accuracy in fitting photosynthetic irradiance curves than the RH model, it can be recommended for accessing the information used in photosynthetic irradiance curves for the leaves of tropical trees growing in Amazonian floodplains or in areas that are artificially flooded by dams. © 2012 Springer-Verlag Berlin Heidelberg

Evaluation of a portable chlorophyll meter to estimate chlorophyll concentrations in leaves of tropical wood species from Amazonian forest

A portable chlorophyll meter can be an important tool to estimating chlorophyll contents in leaves of tree species under field conditions. The method is quick and non-destructive compared to the classic chemical methods of pigment extraction. The aim of this work was to evaluate the performance of a portable chlorophyll meter (CCM-200, Opti-Science) to estimate the concentrations of chloroplastid pigments and the fraction of photosynthetically active irradiance absorbed by leaves (&#945;) in four tropical wood species from Amazonian forest. The results shown positive correlation between the chlorophyll contente index (CCI) readings and concentrations of Chl a (P < 0.0001; r² = 0.904), Chl b (P< 0.0001; r² = 0.803), Chl tot (P< 0.0001; r² = 0.923) and &#945; (P< 0.0001; r² = 0.886), suggesting that the portable chlorophyll meter can be an effective tool for the relative estimation of chlorophyll concentrations and the fraction of the photosynthetically active irradiance absorbed by the leaves of tropical tree species