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F.J. Gómez et al. 2010. Land use changes and mixed forest dynamics. The case of Montiferru Mountains
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Table 2: Changes in mixed forestland area 1955-2006
Sampling
station
Forest patches
Forest gaps
1955-1977
(hectares)
1977-2006
(hectares)
balance
(ha)
% of change
(1955-2006)
1955-2006
(hectares)
MA 6,70 7,18 13,88 28,2 -2,28 -52,0
BM -19,50 0,18 -19,32 -25,3 4,36 69,8
SP -0,17 12,66 12,49 26,2 -1,91 -30,4
AS -3,92 8,25 4,33 7,1 -1,23 -16,4
% of change
(1955-2006)
At species level, 299 oaks and 1.673 holm oaks live trees were counted and measured (per 45
and 430 death, respectively). Widespread, holm oak presents higher observed tree densities and
upper values of basal area (BA) in all the sampling stations than oak that are by mean older;
also, another trend in species composition, documented by the oral sources of information, sets
that nowadays oak density is higher than in previous decades. For land use regimes, the largest
BA and average diameter of trees (and consequently age) are related to high use intensity.
However, certain values of density and basal area take remarkable records in low use recurrence
and abandoned areas (SP & MA) where reforestation is higher (Table 3).
Table 3: Estimated mean values for Q.pubescens (Qp) and Q.ilex (Qi) density, BA, dbh and age
specie MA BM SP AS
Density Qp 485 (330) 270 (211) 295 (216) 445 (349)
(ind/ha) Qi 2.140 (850) 1.580 (494) 2.065 (980) 2.580 (886)
BA Qp 7,23 (8,66) 8,78 (8,75) 5,50 (4,52) 8,22 (5,64)
(m²/ha) Qi 22,33 (8,96) 33,74 (12,71) 28,82 (13,55) 26,36 (10,87)
Mean dbh Qp 7,86 (11,34) 15,2 (12,08) 9,88 (11,56) 12,92 (8,56)
(cm) Qi 7,26 (8,98) 12,5 (10,48) 7,68 (10,22) 8,16 (6,88)
Mean age Qp 18,8 28,7 21,1 24,7
(yr) Qi 17,4 24,6 18,3 18,5
In terms of age structure, significant differences become apparent between use recurrence for
both species (Mann Whitney test for Qp, Z=-2,824 p=0,0047; and Qi, Z=-2,786, p=0,0053) due
to younger age size class: low use recurrence areas presents higher sapling frequencies than pole
ones in contrast to high use recurrence regimes where this pattern reverses (Figure 1). Also, as
proposed indicator of mature forest structure (Barbour et al. 1987) areas of high use recurrence
have better adjustments to reverse J-shaped curves than low use ones where reforestation is
higher. The Differences observed in tree-mortality related to land use regime were statistically
non-significant in both species (Kruskal-Wallis test for Qp, H=1,378, df=3, p=0,7106; and Qi,
H=7,804, df=3, p=0,0502)
Related to regeneration dynamics 139 oak and 1.706 holm oak total ramets were counted (12
and 115 death ones, respectively), and 666 Q.pubescens and 1.298 Q.ilex seedlings too.
As a rule, holm oak presents more resprouting capacity than oak (Mann Whitney test, Z=-7,399,
p