Caracterização fitossociológica da comunidade de trepadeiras e sua rebrota após o corte em uma floresta estacional semidecídua degradada
Resumen
Forests in seasonal tropical regions are increasingly represented by degraded
remnants, exposed to an overabundance of lianas, which inhibit the successional
advance and are often managed by cutting. The research related to this dissertation
was carried out in fragments of seasonal semideciduous forest degraded and
dominated by linas, in the Vassununga State Park, in Santa Rita do Passa Quatro-SP,
Atlantic Forest, Brazil. The dissertation has two chapters, the first one with the objective
of characterizing the liana and tree communities in a degraded forest and the second
chapter evaluating liana resprouting after cutting, in the rain and dry seasons. In
chapter 1, biomass and the relationship of tree and liana communities’ attributes were
evaluated in order to test the hypothesis that basal area and tree density are lower in
areas where liana biomass and density is higher. Plots of 44 m x 45 m were installed,
and trees with height ≥ 1 m were measured and accounted. In subplots of 3 m x 15 m,
the lianas ≥ 0.5 cm in diameter were measured. Liana and tree biomass were
calculated with pre-established allometric equations. We found 45 liana and 191 trees
species. The total biomass (lianas plus trees) was 181.44 Mg. ha-1
. The density of
vines was 12,523 ind. ha
-1 and its biomass was 10.48 Mg. ha-1
(5.77% of the total).
The density of trees was 840.37 ind. ha-1 and its biomass was 170.96 Mg. ha-1
(94.23%
of the total). A ratio of 14.9 individuals of lianas per tree was found, as well as no
correlation was between basal area and tree density with liana biomass. In the second
chapter, 29 plots of 3 x 15 m were established, 12 plots with lianas cut in the rainy
season and 17 in the dry season. The cut of lianas was made at a height of 1 m, in
order to simply break the stem connection, without involving the removal of the cut
material. In the dry season, the percentage of regrowth was 59% and in the rainy
season 52%. The total number of resprouters was 2,178, 1,114 in the rainy and 1,056
in the dry season. The average number of resprouters per individual was 4.2 for the
dry and 3.8 for the rainy season. The average length of resprouters was 47.36 cm for
the dry and 45.48 cm for the rainy season. The average diameter of the resprouters
was 0.29 cm for the dry and 0.28 for the rainy season. All these results did not differ
between seasons. The diametric category with the highest number of resprouters was
the intermediate (2.5 cm ≤ DBH < 5 cm, with 3.9 sprouts), followed by the small (0.5
cm ≤ DBH< 2.5 cm, 3) and the largest (≥ 5 cm DAP, 1.7). Similar results were four for
data regarding resprouters length and diameter. Resprouting varied among species
and, in general, the season of the year does not influence resprouting. The results help
to better understand the balance between richness and biomass of trees in degraded
fragments and the response of hyperabundant lianas to management, supporting
conservation and restoration actions in these forests
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