Afforestation, the conversion of non-forested lands to forest plantations, can sequester atmospheric carbon dioxide, but the rapid growth and harvesting of biomass may deplete nutrients and degrade soils if managed improperly. The goal of this study is to evaluate how afforestation affects mineral soil quality, including pH, sodium, exchangeable cations, organic carbon, and nitrogen, and to examine the magnitude of these changes regionally where afforestation rates are high. We also examine potential mechanisms to reduce the impacts of afforestation on soils and to maintain long-term productivity. Across diverse plantation types (153 sites) to a depth of 30 cm of mineral soil, we observed significant decreases in nutrient cations (Ca, K, Mg), increases in sodium (Na), or both with afforestation. Across the data set, afforestation reduced soil concentrations of the macronutrient Ca by 29% on average (P , 0.05). Afforestation by Pinus alone decreased soil K by 23% (P , 0.05). Overall, plantations of all genera also led to a mean 71% increase of soil Na (P , 0.05). Mean pH decreased 0.3 units (P , 0.05) with afforestation. Afforestation caused a 6.7% and 15% (P , 0.05) decrease in soil C and N content respectively, though the effect was driven principally by Pinus plantations (15% and 20% decrease, P , 0.05). Carbon to nitrogen ratios in soils under plantations were 5.7-11.6% higher (P , 0.05). In several regions with high rates of afforestation, cumulative losses of N, Ca, and Mg are likely in the range of tens of millions of metric tons. The decreases indicate that trees take up considerable amounts of nutrients from soils; harvesting this biomass repeatedly could impair long-term soil fertility and productivity in some locations. Based on this study and a review of other literature, we suggest that proper site preparation and sustainable harvest practices, such as avoiding the removal or burning of harvest residue, could minimize the impact of afforestation on soils. These sustainable practices would in turn slow soil compaction, erosion, and organic matter loss, maintaining soil fertility to the greatest extent possible.

/pdf/a-global-meta-analysis-of-soil-exchangeable-cations-ph-4jtmtopit9.pdf

A global meta-analysis of soil exchangeable cations, pH, carbon, and nitrogen with afforestation.

http://www.cof.orst.edu/cof/fs/kpuettmann/FE%202%202015.pdf

Silvicultural alternatives to conventional even-aged forest management - what limits global adoption?

Assessment of ecosystem services as an opportunity for the conservation and management of native forests in Chile

http://www.srs.fs.usda.gov/pubs/ja/2015/ja_2015_mcnulty_001.pdf

Effects of forest management on productivity and carbon sequestration: A review and hypothesis

The Amazon Basin appears poised to experience rapid expansion of oil palm agriculture. Nearly half of Amazonia is suitable for oil palm cultivation, and Malaysian corporations are now moving into the region to establish new plantations while the Brazilian government is considering a law that would count oil palm as “forest” towards a landowner’s forest reserve requirement. Strong economic incentives for a major Amazonian oil palm industry are likely, given growing global demands for edible oils, oil-based products, and biofuel feedstocks. We have two main concerns. First, oil palm plantations are ecologically depauperate, supporting little forest-dependent wildlife. Second, we disbelieve political and corporate statements suggesting that oil palm plantations will be concentrated on previously deforested lands in Amazonia. In reality, oil palm producers strongly favor clearing primary forest for plantations because they can reap immediate profits from timber production. These profits subsidize the costs of plantation establishment and maintenance for the initial 3-5 years until the oil palm plantations become profitable. Hence, oil palm agriculture could soon emerge as a major new threat to the Amazonian environment.

/pdf/is-oil-palm-the-next-emerging-threat-to-the-amazon-ctdho6ewg5.pdf

Is Oil Palm the Next Emerging Threat to the Amazon

Timber investment returns were estimated for the principal exotic and selected native species in the Southern Cone of Latin America and in the Southern United States. Exotic eucalyptus plantations in South America were most profitable, with internal rates of returns (IRRs) ranging from 13% to 23%, followed by exotic loblolly pine, with IRRs from 9% to 17%. Average loblolly pine plantation returns in the US South were less profitable, with an IRR of about 9.5%, and natural forest management in the South had IRRs of 4% to 8%. Subtropical native species plantations of the best araucaria and nothofagus species had reasonable financial returns, with IRRs ranging from 5% to 13%. Subtropical or tropical native forests had fewer commercial timber species, and had much lower growth rates and returns. Their IRRs were less than 4%, or even negative for unmanaged stands. State subsidy payments for forest plantations or for timber stand improvements increased IRRs somewhat and reserving areas for environmental protection reduced their IRRs slightly. Including land costs in the cash flows decreased these internal rates of return substantially. Natural stand returns in Latin America were much less than those of plantations, but management of those stands offered better rates of return than only holding the land.

Timber investment returns for selected plantations and native forests in South America and the Southern United States

ABSTRACT Brazil has advanced in export volume but has not been able to increase prices over the last decade for wood products. This work seeks to contribute to the understanding of this conflicting scenario, evaluating the growth in the revenue of Brazilian exports of these products during two periods: 2011-2015 and 2016-2020, as well as decomposing its effects in price, exchange rate, and volume. The method applied was the shift-share, widely used to identify determinants of sectoral and regional economic growth, being a precursor to the approach in the analysis of forest sector exports. Historical series for 5 (five) categories of wood products were analyzed, with export data from the Ministry of Economy. The historical series of nominal exchange rates from the Institute of Applied Economic Research (IPEA) was used. The real effective exchange rate (RER) followed the methodological note of the IPEA. All product categories analyzed had positive effects in terms of volume, for both periods, with a greater proportion in the second being driven by the exchange rate, although with a loss in real price, failing to offset inflation. The only exception was wood manufacturers, a product with higher added value, which presented gains in volume, exchange rates, and price. The volume effect was the most relevant, followed by the exchange rate as a result of the appreciation of the dollar against the real against the exchange rate and control of inflation in terms of the divergent effects on the national and international scenario. The price presented negative variations in export revenue, with a decline over the period. In addition to the added value of exported products, world stocks and levels of consumption may have contributed negatively to this scenario, affecting all categories of exported products, except for manufactured wood products, the only category that did not reflect such justifications.

/pdf/evaluation-of-the-effects-of-price-exchange-and-volume-on-1nh1qfwx.pdf

José Sawinski Júnior

Papers

Timber investment returns for selected plantations and native forests in South America and the Southern United States

Evaluation of the effects of price, exchange, and volume on the growth of revenues from brazilian exports of wood products