RESUMEN

Thinning woody biomass to reduce wildfire risk has become a common forest management prescription throughout the Intermountain West. Converting the resulting slash into biochar, a carbon-rich soil amendment, could help mitigate some of the shortcomings of other fuel treatments, but land managers in the western United States have not widely adopted biochar, despite its potential benefits and new government incentives. Thus, we investigated the often under-studied sociocultural, economic, and biophysical barriers to biochar production and identified important factors to inform future outreach efforts that will help to expand biochar production from thinning slash in northern New Mexico. We distributed surveys and conducted interviews with land managers and personnel working in environment conservation organizations who work with land managers throughout northern New Mexico. We found that 65% of participants (n = 60) were familiar with biochar, and 13% already produced biochar. Participants identified improving soil and reducing forest fuel loads as the main benefits of biochar. The most prevalent barriers to adopting biochar were insufficient knowledge about biochar production and its application and concerns about production costs. Given land manager preferences, outreach efforts to encourage biochar adoption should focus on hands-on informational activities. Barriers and preferred outreach methods varied by participant race and familiarity with biochar. With appropriate training to empower land managers, biochar can provide environmental and community benefits by the sustainable conversion of forest residues into a soil enhancement product that would be beneficial to northern New Mexico's dry, high wildfire risk context.

Asunto(s)

Carbón Orgánico , New Mexico , Conservación de los Recursos Naturales , Suelo , Agricultura Forestal , Bosques , Biomasa , Incendios Forestales

RESUMEN

For millennia, Maya farmers (i.e., milperos) throughout Mesoamerica have managed milpa: sequential agroforests initiated by slashing and burning patches of secondary forest and then cultivating a diverse polyculture of trees and annual crops. To reduce greenhouse gas emissions associated with deforestation, the Mexican government and non-governmental organizations have urged milperos to cease burning. We collaborated with Maya milperos in several communities in the Montes Azules Biosphere Reserve region in Chiapas, Mexico to determine carbon retained as char in traditional milpas, carbon loss associated with burning, and effects of burning on soil quality. We found the carbon retention of char in Maya milpas (24 ± 6.5% of C in vegetation) is 4-1400% higher than other slash-and-burn agroecosystems reported in the literature. Burning resulted in significant carbon loss of 12.6 (±3.6) t C ha-1 yr-1, but this was partially mitigated by char production (3.0 [±0.6] t C ha-1 yr-1) and incomplete combustion of woody biomass. The effects of burning on soil were minimal, with the only significant changes observed being increases in pH, potassium availability, and cation exchange capacity (2, 100, and 7%, respectively). The mean residence times of charred materials were at least double that of uncharred biomass. While there is a risk that shortening fallow periods would undermine the sustainability of Maya swidden agroecology, proper management and secure land tenure can help maintain intensive production without enduring environmental degradation. The char produced in these swiddens and successional management could allow this agroforestry system to be a long-term carbon sink.

Asunto(s)

Bosques , Suelo , México , Árboles , Carbono , Agricultura

RESUMEN

We aim to answer a question: how does the geological setting affect flood dynamics in lowland alluvial rivers? The study area covers three river reaches: not trained, relatively large on the European scale, flowing in broad valleys cut in the landscape of old glacial plains. We focus on the locations where levees [both: a) natural or b) artificial] were breached during flood. In these locations we identify (1) the erosional traces of flood (crevasse channels) on the floodplain displayed on DEM derived from ALS LIDAR. In the main river channel, we perform drillings in order to measure the depth of the suballuvial surface and to locate (2) the protrusions of bedrock resistant to erosion. We juxtapose on one map: (1) the floodplain geomorphology with (2) the geological data from the river channel. The results from each of the three study reaches are presented on maps prepared in the same manner in order to enable a comparison of the regularities of fluvial processes written in (1) the landscape and driven by (2) the geological setting. These processes act in different river reaches: (a) not embanked and dominated by ice jam floods, (b) embanked and dominated by rainfall and ice jam floods. We also analyse hydrological data to present hydrodynamic descriptions of the flood. Our principal results indicate similarity of (1) distinctive erosional patterns and (2) specific geological features in all three study reaches. We draw the conclusion: protrusions of suballuvial bedrock control the flood dynamics in alluvial rivers. It happens in both types of rivers. In areas where the floodplain remains natural, the river inundates freely during every flood. In other areas the floodplain has been reclaimed by humans who constructed an artificial levee system, which protects the flood-prone area from inundation, until levee breach occurs.