ND-11 Abstract

Carbon and Nutrient Stocks and Regrowth in Reduced Impact and Conventionally Logged Forests and Settlements in NW Mato Grosso, Brazil

Eduardo Guimarães Couto, Universidade Federal de Mato Grosso (SA-PI)
Erick C.M. Fernandes, Cornell University (US-PI)
Carlos Passos,  (SA-PI)

Science Questions

CD-Q3b. How does selective logging change the storage and cycling of carbon in forests?

CD-Q3c. What factors (biologically mediated, land use history, soil properties, etc.) control the rate of carbon sequestration in biomass and soils of regrowing forest?

ND-Q1. How do stocks, cycling rates and budgets of carbon and important elements nitrogen, phosphorus, potassium, calcium, magnesium, and aluminum change under different land covers and land uses?

ND-Q2. Are nutrients major factors that control the rates of regrowth and carbon accumulation in abandoned pastures and regrowing secondary forests?

ND-Q4a - How will the composition and quantity of nutrients and organic matter entering and being processed within streams be altered under different land-use change scenarios?

Research Approach

Our major focus will be on the questions “What are the impacts of conventional and reduced impact logging on above and belowground carbon and nutrient stocks and water and nutrient fluxes and how do these impacts change over time following the logging?” Answering these carbon and nutrient dynamics science questions will require ground-based biogeochemical studies and the enhancement and use of currently available GIS techniques.

The specific goals of our project are to: (1) Measure existing forest biomass (carbon) and nutrient stocks and validate available models for estimating forest biomass. (2) Quantify the impact of soil texture and fertility gradients on above and belowground C and nutrient stocks in local forests, and (3) Measure the impact of conventional (CL) versus reduced impact logging (RIL) on C dynamics. If time and funds permit, we will also obtain measurements on the quantity and composition of sediment, nutrients, water and organic matter entering first order streams.

We will estimate aboveground live biomass in primary forest using four alternative allometric equations that were calculated for moist tropical forest trees and fine-tune these estimates with destructive sampling and direct measurements of trees in similar forests and soils at settlement sites adjacent to primary forest on our site. Because settlers completely clear the forest for agriculture on 20-30% of their land, we will be able to use destructive harvests for all DBH size classes and then estimate the biomass contribution of bole extensions belowground. We will also use the plots on settlements to directly measure vine and epiphyte biomass and relate this to aboveground tree biomass.

We propose to quantify the impact of soil texture and fertility gradients on above and belowground C and nutrient stocks in local forests. We will use an empirical and a modeling approach to examine the relationship of soil texture, especially clay content, to patterns in above and belowground C and nutrient pools. Our site is characterized by an Oxisol-Ultisol-Entisol association that is commonly found across the Amazon basin. To examine the role of texture in greater detail, and to test mechanisms by which texture influences the biogeochemistry of moist lowland tropical forests, we will use the Century model to simulate the forest on the different soil textural classes at our site. Our data will contribute significantly to the robustness and reliability of existing allometric equations for forest biomass across the Amazon.

In addition, our site has a 10 year chronosequence of selective, conventional (CL) and reduced impact logging (RIL). We propose to evaluate the We will use the data from the studies mentioned above to measure the impact of CL and RIL on above and belowground C and nutrient dynamics. The removal of trees inevitably leads to nutrient export from the forest ecosystem. It is unclear to what extent nutrients are distributed among topsoil, subsoil, litter layer, standing biomass and streams by selective logging. We will collaborate with Richey et al. (CD-06) to link our measurements of C and nutrient flows to first order streams with local rivers. We are collaborating with Asner et al (LC-13) to evaluate canopy damage and the hyperspectral signatures of various stages in the selective logging chronosequence – from primary forest to the logging event to regrowth. Our links with work in CD-06 and LC 13 will contribute to the assessments of the impacts of selective logging on carbon management at the basin scale.

Site areas:  Municipality of Juruena, NW Mato Grosso.

[GPS coordinates: S 10 25’ 29.7; W 58 45’ 34.9]

Field Work Dates:

1.   Continuous Field Measurements: March 2003 - August 2004 (for soil and water measurements)

2.   Field Campaigns: May-September, 2003 and 2004 (for above- and belowground forest biomass and nutrients; ground support for AVIRIS)

Field Measurements:

A.   Establish permanent forest sample plots for biomass and tree mortality. Ground damage mapping of selective logging: Forest surveys including tape, compass, Differential GPS.

B.   Above and belowground tree biomass: Destructive tree harvest, stump extraction, coarse and fine root estimates: (Skidder, balances, drying ovens, tapes, chainsaws)

C.   Canopy gap fraction and leaf area index (LAI): Licor LAI-2000 Instruments

D.   Aboveground biomass in coarse woody debris and removed in logs: Forest surveys and wood sampling.

E.    Soil, Foliar, Wood, Stream nutrients (cations, anions). Laboratory based wet chemistry.

Education and Training Plan:

A.     Short courses/workshops/seminars

Graduate seminar series on Forest Ecology and Management for 30 students at UFMT (Couto, Passos, Fernandes, Lehmann, Riha, Oelbermann)

Ten-day field course for 30 UFMT Forestry/Soils MS-level students (Couto, Passos, Fernandes, Lehmann, Riha, Oelbermann)

Two-day forest mensuration and data processing course for 10 UFMT forestry undergraduates (Passos, Fernandes)

Half-day workshop on Forest Management, Productivity and Ecosystem services for UFMT professors, students, and MT officers of IBAMA, FEMA, Secretariat of Science and Technology and Environment (Couto, Passos, Fernandes, Lehmann, Riha, Oelbermann)

   B. Students/Interns

Five Brazilian and two US graduate students in forest science/Soil Science working on MS & PhD research (Fernandes, Passos, Couto, Lehmann, Riha)

C. Technology Transfer

Field measurement techniques/equipment for forest biomass, soil and foliar nutrients, canopy damage and coarse woody debris (CWD) estimation.