Selective logging in Amazonia : forest structure, damage and biogeochemical changes / by Ted Ronald Feldpausch.

Tese (Ph.D.)--Cornell University, 2006.

Chapter 1 presents one of the first spatially explicit landscape estimates in Amazonia of forest and commercial timber properties based on a large-scale inventory of 20000 georeferenced trees. Combining a commercial timber inventory (CTI), scientific inventory, and remotely sensed reflectance (LANDSAT TM) and topographic properties (ASTER-derived), we (1) determined the area unavailable for logging based on 50 m stream buffers and areas without commercial timber species, (2) tested if there is a relationship between commercial timber vegetation and reflectance and landscape properties, (3) evaluated if it is possible to estimate total aboveground biomass of all trees and palms ( = 10 cm DBH) from the CTI alone. Chapter 2 examines carbon export in whole logs and carbon accumulation as coarse woody debris (CWD) produced from forest damage during all phases of the first and second year of a certified Reduced Impact Logging (RIL) timber harvest in southern Amazonia. Our measurements included a 100% survey of roads and log decks, assessment of canopy damage and ground disturbance in skid trails and tree-fall gaps, and measurement of carbon exported from the site in logs. Our results indicate that certified timber harvest in Amazonia under RIL is a viable forest management option to reduce damage and CWD production compared to conventional logging (CL) practices; however, the benefits of disturbance reduction from RIL relative to CL are only realized at greater volumes of timber extraction. Chapter 3 quantifies changes in forest structure and soil nitrogen (N) to test whether N loss from leaves and CWD under RIL results in a significant accumulation of soil nitrate to 8 m depth. To evaluate the effect of RIL activities on N pools, we measured N export in logs, soil N stocks, canopy reduction, CWD generated from all logging activities (road and log deck construction, skid trails, and logged-gaps) and soil moisture in surface soils and nitrate to 8 m depth in logged gaps and intact forest. At the low harvest rate and disturbance intensity of this study, soil N storage and nitrate accumulation to depth are within the ranges of undisturbed forest, suggesting that N losses from RIL will be primarily restricted to other exports, such as in boles and denitrification.