The present study had the objective of evaluate the deposit and
decomposition of litter and characterize the phitossociology of
two distinctive
forestation: heterogeneous plantation
and
homogeneous
plantation
with
Mimosa
caesalpiniifolia(sabiá)
specie. Both were implanted as conservacionists actions to
recuperate and contain slopes at Grajaú State Park. The fallen
material from the trees, were colleted monthly through 10 conics
collectors installed in each study area. This material was
separated in leaves, branches, seeds, flowers, shell, and
others. After this separation, the material was dried and
weighted. A part of the leaves fraction was put in litter bags,
used to estimate the decomposition of the material. There were
installed 9 litter bags in each area containing 10g of the
vegetal material. There were taken from the ground in 30, 60 and
90 days, after the installation. The remnants material in each
time was milled and sent to analysis of C, N and poliphenois.
The analysis of soil fertility was also made and the
phitossociology characterization, by the sampling method in
parcels. There were identified 21 species, allocated in 19
generous and 10 families, in total of 97 individuals. Fab.
Papilionoideae presented most species in total of 6. The species
Anadenanthera
macrocarpa
(18,56%),
Mimosa
caesalpiniifolia
(14,43%), Dalbergia nigra (10,31%), Joannesia princeps (9,28%) e
Peltophorum dubium (8,25%) represented 60,83% of the total
individuals, presenting higher relative density. The five
species with higher relative frequencies were: Anadenanthera
macrocarpa
(14,55%),
Dalbergia
nigra
(10,91%),
Mimosa
caesalpiniifolia
(10,91%),
Peltophorum
dubium
(10,91%)
e
Machaerium nyctitans (7,27%). Two of the five species of higher
importance, are classified as not-pioneers: Joannesia princeps e
Dalbergia nigra. The pattern of deposit apported 3,71 ton/ha and
4,01 ton/há on the homogeneous plantation and heterogeneous
plantation, respectively. The leaves fraction presented higher
values, 73 %, on the homogeneous plantation and 85 % on the
heterogeneous plantation. The decomposition is happening in a
faster way on the sabiá plantation. The result of
soil
fertility are similar to those found on forests soils. The
forestation presented a vegetal structure capable of covering
the soil and seems to offer protection against erosive process.
But, on the homogeneous plantation, this function can be
decreased by the higher number of trees on a senescence stage
and the absent of a young tree nursery that will come to
substitute these trees.
