Effects of different techniques of treating pruning and thinning residues on some soil properties of afforestations of Patagonia located in a precipitation gradient: preliminary results

NATALIA SOLEDAD LEDERER; MARÍA MELISA RAGO; MARÍA MARCELA GODOY; GUILLERMO EMILIO DEFOSSÉ

San Antonio

Congreso; 6th International Fire Ecology and Management Congress; 2015

The Association for Fire Ecology

Conifer afforestation is an incipient activity in the forest- steppe ecotone of Andean Patagonia, Argentina. Of about 800 thousand ha with good afforestation potential, only 90 thousand ha are already planted. Most of them lack of silvicultural practices such as pruning and thinning, and when they are executed, residues are left on site untreated. This study was aimed at a)quantifying these residues in three pruned and thinned stands located in a precipitation gradient comprising humid, mesic and dry sites; and b)determining the effects that three techniques of reducing residues, namely 1)prescribed burning, 2) mastication, 3) mastication plus prescribed burning, and4) control, have on some soil properties. Before treatment, fuel load of residues (coarse, medium, and fine) was similar on the three sites. Results showed that Site 1 presented the highest values of OM as compared to Site 2. In both cases, OM fluctuations were low and the treatments had little influence in OM dynamics. Non significant differences were found due to treatments on either site, although they were different between sites and in the 0 to 5 cm soil depth in Site 1. In the case of soil pH, the same trend was found when comparing the values observed within treatments of Sites 1 and 2. Related to soil moisture, only the burn treatment showed lower values than the rest of the treatments on the three sites.