Sasso Fratino Nature Reserve (National Park of Casentino Forests, northern Apennines) is a quite rare example of natural Apennine forest. The Reserve was established in 1959, aiming to protect a forest, although not a virgin one, low-intensively disturbed in the past by comparison with other neighbouring stands. Causes of such a low disturbance are the very limited accessibility of the area due to the very steep slopes characterising the site morphology, as well as historical features. The forest is a pure beech stand from 1250 m a.s.l. upwards, below this altitude is a mixed beech and silver fir forest. The study focuses on the understanding of the processes driving the evolution of the forest in the absence of human activities. To achieve this goal, 9 permanent, long-term research plots were established at different altitudes, in order to investigate on forest dynamics and regeneration processes. Simplified (single-layer) stand structures are more frequent where canopy gaps are absent. Two-layered structures are the result of the occurrence of canopy gaps, which allow the settlement, and subsequently the establishment, of a lower regeneration layer. Where the gap dimensions allow canopy closure, this kind of structure persists. When the gaps are quite large, the regeneration layer reaches the top layer and the structure stand tends, once more, toward a single-layer. Multilayered structures are extremely rare at plot level and become evident only at a wider scale. Our surveys indicate also a high variability of tree diameter distribution patterns in the forest stands. Such variability could be strictly related to the heterogeneity of site characteristics as well as to the effects of disturbance factors (both natural and anthropic). Concerning altitude, we observed an increase both of site index (dominant height) and species diversity in the regeneration layer, moving from higher (1500 m) to lower (900 m) altitudes. As a whole, our observations show that the dynamics of forest vegetation in the reserve is mostly affected by the interruption of tree canopy continuity. This implies substantial local variations of PAR in space and in time, which determine favourable ecological conditions for: (a) survival and growth of beech seedlings, or release of advanced beech regeneration; and (b) release of advanced silver fir regeneration (fir, more shade tolerant than beech, regenerates mainly in locations and conditions where the broadleaf saplings cannot survive for lack of light). The knowledge of the mechanisms of vegetation dynamics in the Reserve can be used to form the basis of close-to-nature silvicultural choices in similar stands in order to increase functionality and stability. Periodical monitoring of RNI will allow the investigation of the evolutionary trends of the forest stands.
Forest stand structure is the result of the environmental history of a phytocoenosis and includes anthropic influences. The study of the disturbances and structural dynamics of forest ecosystems that have not been influenced by human activity is one of the most effective approaches to describe and understand stand dynamics for the application of close-to-nature silviculture (
Fully-protected, natural forest reserves play the role of living laboratories, where the processes responsible for forest dynamics can be analysed and monitored over time. Studies on the structure and dynamics of beech-dominated woods are frequent in the central and northern areas of the natural range of
The beech-dominated Apennine woods cover an area of roughly 600 000 hectares (
A number of factors affect the present physiognomy (in terms of spatial structure and composition) of the Italian beech woods. Foremost, in its ecological
According to the first studies conducted in the Reserve of Sasso Fratino (RNI), forest stands were considered similar to a virgin forest (
The most recent timber harvest in the forest (reconstructed using the management plan for the years 1934-1943) was conducted by the State Forestry Agency. The research area is described as “dense and mature beech and fir mixed stands with the presence of abundant regeneration on almost the whole area, mainly in the upper sector where the tree density is lower and the distribution even”. The latest documented timber harvest was in 1936 and consisted of 325 m3 of timber (80 beech logs for a total of 42 m3 and 608 silver fir trunks for a total of 283 m3) and 22.8 steres of beech fuelwood (15 charcoal areas homogeneously distributed in altitude were pointed out by
At present, because of the lack of anthropic influences over the last seven decades, Sasso Fratino is considered as one of the best examples of old growth and natural forests in Italy.
In the framework of Italian forests, RNI represents a living laboratory of inestimable value because it shows the results of natural processes working without human influence over the last seventy years. Research in the RNI has been carried out for decades (
The Natural Integral Reserve of Sasso Fratino is located in Central Italy in the northern portion of the Tuscany and Romagna Apennines (latitude 43°11’ N; longitude 11°47’E). The reserve covers an area of roughly 780 hectares. The elevation ranges between 650 and 1520 m a.s.l. Morphology is irregular, with an average slope higher than 65% and often 100%, and rock crags are frequent.
The bedrock of the area is the Miocene sandstone marl series (Romagnola
The average annual temperature is 9° C and the annual temperature excursion is 16.4° C. Average annual rainfall is 1750 mm, 255 mm of which falls in the summer. Atmospheric moisture is high throughout the year and foggy days (48 days in average) are quite frequent during the growing season. Snow cover lasts about 3 months from December to February. The prevailing winds blow from SW and NE and can be blustery along the ridges. Based on the Rivas-Martinez classification (
The study was carried out in the original RNI nucleus (about 113 hectares), which has been under full protection since 1959. The study area stretches from Poggio Scali (1520 m a.s.l.) to the confluence of the Acqua Fredda and Sasso Fratino (900 m a.s.l.) streams.
In order to sample all of the RNI stands, a general survey of the present physiognomy of the stands was carried out over the entire study area. After the large-scale survey, two different aspects were investigated.
First, a survey of the representative flora of the RNI was conducted in 9 plots located at different altitudes. Each plot was named with the prefix SF and numbered from 1 to 9 in relation to decreasing altitude. Data were collected 5 times for each plot during the growing season (May 6, May 17, June 3, June 22, and August 2, 2005). The plots were circular with a 10 m radius. The species were determined using the reference of the
Five out of the 9 plots were selected for this survey as the most representative of the stand physiognomy observed within the entire study area. A 1000 m2 transect plot (50 x 20 m, subdivided into four 250 m2 - 20 x 10 m sub-plots) was permanently outlined. The following parameters were recorded for each woody plant higher than 150 cm: species, position, diameter (d), total height (h), crown depth and crown ground projection (according to four perpendicular radius lines). In a 300 m2 transect plot (50 x 6 m, further subdivided into 6 sections - 10 x 6 m across the medium line of the former plots), species, position and height were recorded for each individual woody plant lower than 150 cm. In order to obtain indirect data about the canopy cover, the relative irradiance (I.R.) within the PAR range was measured using two ceptometers (Sunscan Canopy Analysis System, AT Delta-T Devices, Ltd). During July and August 2005, two measurements, one under canopy cover and the other in open space (as control) were taken simultaneously during mid-daylight hours, precisely between 11:30 and 1:30 p.m. (standard time), in sunny conditions.
Data were processed in order to summarize the main characteristics of the stand structure: the number of plants and basal area per hectare (n ha-1, G ha-1), average tree height of the individuals belonging to the upper layer (Hm), and frequency of trees in terms of diameter (10 cm interval) and height (5 m interval) class. In order to describe the spatial structures, 3 canopy layers were identified: the lower layer (regeneration layer, up to 3m height), the upper layer (composed of individuals of the two top height classes), and the medium layer, including the remaining trees. The spatial structure of the stand was described on the basis of the reciprocal position of the trees in the frame of single tree-clusters along the stand profile.
The average density of the individuals in the natural regeneration layer was calculated for each section, while the diversity level was evaluated applying the Shannon index (HS). Concerning the floristic investigations, the biological spectrum was determined on the basis of the frequency of biological forms. Furthermore, the Ellenberg’s ecological indices (
where
The Kolomogorov-Smirnov (KS) and Weibull function (Wf) were used to evaluate and compare the distribution of diameters, in particular comparing the C form parameter of this function: if C < 1, then J reversed function; if 1 < 3.6, then the mound bell shaped function was positively skewed; if C ≈ 3.6 then there was a normal distribution (
According to our observations, the present situation is very similar to the one described above: beech is the dominant species over the entire area in terms both individual trees and biomass. At higher altitudes, where the slope is steeper, the soil is shallower and the wind more violent (especially in proximity to the ridges), the forest stand structure is rather similar to an aged coppice. The most frequent canopy profile is double-layered, consisting of an upper layer (18 m < h < 24 m) where big trees were present, mostly beech (D > 60 cm) with a few scattered sycamores, in an even distribution. The canopy cover is discontinuous. Individuals of beech, sycomore maple, European hornbeam and, less frequently, mountain ash are present in the lower layer (h<3 m). The tree space distribution is irregular and the structure is similar to a former coppice woodland.
At lower altitudes, the steepness of the slope decreases, soil thickness increases and wind influence is less noticeable. The stands show a physiognomy of mature and well-developed beech forests. The spatial structures vary according to former harvesting and, locally, to the action of natural abiotic factors. The canopy gaps are due to the collapse of one or a few plants. The only exception is a 1.5 hectare area located near the eastern border, where a landslide completely removed the forest stand in 1982. The area was colonized by
In canopy gaps, natural regeneration of beech, and less frequently sycomore maple, European ash and silver fir, is observed. In the smaller gaps, the edge trees tend to expand the crown to fill the available space: this process created a double-layered structure where beech regeneration shows symptoms of overshading. Where the canopy gaps are wider, progressive establishment and growth of natural regeneration has been observed: the spatial structure is double-layered, but in this case, evolves quite rapidly to a one-layered, because of the fast growth of the individuals in the regeneration layer.
The stands without canopy gaps exhibit a single layer structure. Beech trees (H > 30 m) are evenly distributed, sometimes alternating with single trees or small groups of sycamore and silver fir. The canopy cover is almost complete. At altitudes below 1300 m, and more frequently below 1200 m a.s.l., small groups or isolated individual silver fir and European yew (sporadic) trees, lower than 3 m, could be observed. Below 950 m a.s.l., planted silver fir stands are more frequent. Broadleaf regeneration, mainly beech, has been observed under the silver fir canopy.
Due to the objectives of the study, the floristic and phytosociological aspects should be considered only as a completion of the general description of the forest research area. The floristic check list (
Species typical of beech forests, such as
Frequency analysis of the biological forms (
The Ellenberg’s indices analysis show the absence of light sensitive species (values: 8-9). The frequency of light insensitive species is very low (<10%) as well. In all plots, species characteristic of the high mountain environments (value 1) are present, and by contrast, warm-sensitive species (values 8-9) are absent. Species indicating intermediate mountain temperatures (value 5) are the most frequent. The percentage of species adapted to moderately cold climates (value 3) decreases along the elevation gradient from plot SF1 to SF9; these species dominate the floristic composition of SF1 and SF2. The frequency of temperature insensitive species is very high, although it decreases from SF1 to SF9. This result demonstrates that temperature is a less selective factor than light in the study area. Species with strict oceanic requirements (value 1) have not been found in any plot, but are were plenty of oceanic and sub-oceanic species (values 2, 3, and 4). Continental or sub-continental species are very few, as well as continental-insensitive species. This confirms that the climate is oceanic according to the
According to the Jacquard index, all of the plots are rather dissimilar. In fact, the value is always below 0.5, with the exception of the comparison between plots SF6 and SF9 (0.57). This result indicates that different stand structures correspond to different floristic compositions on the ground floor.
In
SF1 is located in proximity of the forest ridge (1480 m a.s.l.) on a slope facing northeast. The slope average is 70% with peaks over 100%. The forest profile is double-layered and is composed of 770 trees per hectare with a 50.5 m2 basal area. The upper layer (18 m < 24 m) is characterized by almost continuous cover. In term of individuals, beech is over 70% of the species present, mostly from gamic origin (70%), while the remaining is composed of tree stump shoots (30%). The other tree species are sycamores, equally subdivided between plants from gamic origin and tree stump suckers. The lower layer (H < 10 m) presents a discontinuous cover, not exceeding 30%; beech is the dominant species, with sycamore contributing 15% of the individuals. In both cases, most of the individuals are originated from seed. The diameter distribution is represented by two parallel distribution curves, each resemble to the even-aged type. One results from the plants occupying the lower layer (diameter of the first three classes ranging from 5 to 25 cm) and the other includes the mature trees of the upper layer (diameter from 35 to 95 cm).
SF3 is located about 50 m below SF1, completely facing northeast, though the slope is smoother and never exceeds 50%. The stand profile is single-layered (20-28 m), characterized by full tree cover: the tree density is 360 beech per hectare, the basal area is 50.5 m2. The specific composition is dominated by beech, while sycamore is fairly sporadic and distributed as single trees or in small groups (2-3 individuals). Few beech individuals (2-10 m) under canopy cover are present and those few individuals are irregularly distributed. The diameter distribution is similar to an even-aged forest curve with modal and median values coinciding in class 45 cm.
SF4 is located just below SF3 with similar slope conditions. The physiognomy is also similar, although in this case the forest profile is double-layered and composed of 1370 trees per hectare, with 42.9 m2 basal area. The upper layer (20-30 m) has almost complete canopy cover, with localized and small (50-60 m2) gaps. Beech is the dominant species of the stand (90% of the individuals) with a few individual sycamores, placed in dominant or co-dominant positions. In the lower layer (H < 8 m), beech individuals from gamic origin are clumped in dense clusters. The trees of this layer show symptoms of shading disease: most of the plants have small diameters, besides the plagiotropic growth pattern of the main axis. The diameter distribution approximates an even-aged stand, modal class 45 cm, with another peak in the first two diameter classes because of the presence of the natural regeneration.
SF5 is located at an altitude of 1300 m a.s.l. on an east-facing slope. The forest profile is double-layered, despite a tendency to being multi-layered in some locations. Some 910 beech trees per hectare with a 43.8 m2 of basal area have been recorded. Only beech (25-32 m) is present in the upper tree layer, and the canopy cover is irregular. The lower layer (12-20 m) is characterized only by beech, mostly from gamic origin. Sparse groups of small beeches (2-5 m) are not enough to constitute a definite layer. All of the individuals present in the lower layer show vigorous aspect. Diameter distribution tends to an uneven-aged stand, because of the simultaneous presence of a regeneration layer (5 to 15 cm diametric classes) and mature trees of the upper layer (last four diameter classes).
SF8 is located at an altitude of 1100 m, facing east on level ground. The forest profile is mono-layered (38-44 m) and the canopy cover is complete. There are 140 trees per hectare, with a basal area of 50.3 m2. A discontinuous intermediate layer, composed of a few sparse silver fir trees (H 12-15 m), occurs mainly close to the gap edges. Individuals of this species are also present at the floor level (H 2-5 m). On the whole, canopy cover is low. The distribution of diameter classes is almost even-aged (modal class 75 cm), although the presence of silver fir in the lower layers creates an asymmetry to the left side of the distribution curve.
Comparing the diameter distribution of the five plots by the KS test, very significant differences emerge (p<0.01). C values of the Weibull function are quoted in
The Chi-square indicates a distribution of non-homogeneous individuals in the three layers among the five plots (χ2 [8] = 143.6, p<0.01). The values of the χ2 test are reported in
The results, listed separately for each plot, can be summarized as follows:
SF1, 4833 saplings per hectare (65% sycamore, 34% beech, 1% European elm) with an average height of 6.5 cm (± 2.0 SD)
SF3, 2233 saplings per hectare (58% sycamore, 40% beech, 2% silver fir) with an average height of 5.9 cm (± 1.7 SD)
SF4, 19400 saplings per hectare (51% beech, 48% sycamore, 1% ash) with an average height of 6.3 cm (± 2.1 SD)
SF5, 18567 saplings per hectare (70% beech, 28% sycamore, 2% silver fir, ash, lime and common laburnum) with an average height of 6.7 cm (± 2.8 SD)
SF8, 11767 saplings per hectare (66% silver fir, 24% sycamore, 8% beech, 2% ash and lime) with an average height of 4.4 cm (± 1.9 SD)
In terms of saplings number, ANOVA (
Comparing the average values of HS, ANOVA does not indicate significant differences among plots, mainly due to the strong variability within each plot. A tendency of progressive increase of the middle value of HS with decreasing altitude have been observed (
Considering the average value of I.R., ANOVA shows highly significant differences (p<0.01) among the plots (
Despite the steep slopes and the uneven morphology, the RNI forests were harvested in the past, as indicated by the numerous charcoal areas located throughout the Reserve. The last harvests were seventy years ago, and even if it is not possible to accurately identify the areas where fellings occurred, harvests were probably located only in the most accessible zones considering the small amount of timber that was removed. This could have influenced the large amount of diversity in the spatial structure of the stands (
Composition, development (in terms of both height and density) and distribution of the lower vegetation layers (especially in terms of natural regeneration of saplings) have been determined by site characteristics (especially altitude and soil fertility), past fellings, and the spontaneous occurrence of gaps.
Floristic samples show a considerable lack of species in the study area. In the RNI,
Specific composition plays a key role in the understanding of forest ecosystem dynamics; however, according to
coppicing, which lasted longer on the ridges than in other areas of the forest, due to easier exploitation along the ridge;
wind influence;
combined influence of snow and wind, which could have caused more extended windbreakages in comparison to more protected sites.
Concerning altitude, we observed an increase both of site index (dominant height) and species diversity in the regeneration layer, moving from higher (1500 m) to lower (900 m) altitudes. Indeed, as altitude decreased, the increase in tree height was attributable, as well as bioclimatic factors, to the site morphology: the sites where the slope is more moderate, and which are characterized by deeper soils, were more frequent at lower altitudes. This can also help to explain the lower tree species diversity in the regeneration layer of the higher altitude areas, even if the effect of more selective climatic conditions (shorter vegetative season, more frequent frosts, stronger wind, and more persistent snow) can emphasize this phenomenon. It is also necessary to consider the influence of soil depth on the crown reaction to gap opening: more fertile areas induce a more vigorous reaction and, consequently, faster canopy closure.
Simplified (single-layer) stand structures are more frequent where canopy gaps are absent. Two-layered structures are the result of the occurrence of canopy gaps, which allow the settlement, and subsequently the establishment, of a lower regeneration layer. Where the gap dimensions allow canopy closure, this kind of structure persists. When the gaps are quite large, the regeneration layer reaches the top layer and the structure stand tends, once more, toward a single-layer. Multilayer structures are extremely rare at plot level and become evident only at a larger scale (mosaic of stand structures).
Our surveys indicate a high variability of tree diameter distribution patterns in the forest stands, especially in relation to the observed spatial structures. Such variability could be strictly related to the heterogeneity of site characteristics as well as to the effects of disturbance factors (both natural and anthropic). A study completed in southeastern Europe (
Our observations, therefore, show that the dynamics of forest vegetation in the RNI is mostly affected by the interruption of tree canopy continuity. This implies substantial local variations of PAR in space and in time, which determine favourable ecological conditions for: (a) survival and growth of beech seedlings, or release of advanced beech regeneration; and (b) release of advanced silver fir regeneration.
Beech, the dominant species in both the regeneration and stand layers, more frequently regenerates according to an aggregated spatial distribution, each group corresponding to canopy cover openings originated from the collapse of one or a few individuals of the upper layer, a pattern recently highlighted in research carried out in old-growth
In some cases, according to our data, an important role can be played by advanced regeneration. Although beech saplings can survive under a locally closed canopy, their establishment is hindered by strong competition for light and other resources due to a dense cover of saplings and/or trees. By contrast, the release of beech “advanced regeneration” is favoured by gap occurrence (
Fir, more shade tolerant than beech, regenerates mainly in locations and conditions where the broadleaf saplings cannot survive for lack of light. The chances of regeneration of silver fir are indeed connected to: (1) settlement and initial growth under canopy cover at RI levels of 2-3% (a nearly exclusive niche); and (2) the subsequent occurrence of a gap,
By contrast, our data have shown that, in the Sasso Fratino Reserve, under a dense canopy cover, PAR values at the forest floor are, on average, too low to allow an effective process of natural regeneration, even for shade tolerant species such as silver fir or beech: the recorded values under the continuous canopy cover were in general below 2% of RI, the minimum threshold for the survival of silver fir saplings (
As a whole, natural regeneration of shade tolerant tree species like beech and silver fir (the most abundant in the mountain belt of the RNI) is favoured by the opening of relatively small canopy gaps (
Light is not the only factor affecting silver fir regeneration in the Reserve. It has been observed that silver fir regeneration in central European mixed-beech forests occurs on a small scale, characterized by sparse aggregates. This pattern is not necessarily based on the relation to the degree of canopy cover (light availability), but also to the edaphic variability (the chance of regeneration success of silver fir in open sites of Sasso Fratino is favoured in presence of oligotrophic soils -
The basis of close-to-nature silviculture, commonly accepted as a correct approach for sustainable forest management (
In particular, gap dynamics - with particular regard to aspect, slope, dimension, and canopy closure time - significantly contribute to understanding the role of small scale disturbances in the forest systems (
The near natural forest of Sasso Fratino represents a basic reference for nature-based silviculture of beech and mixed beech forests in the Apennines. According to this work, as well as to other studies in near-natural temperate mixed forests of the mountain belt, the evolutionary trend is not homogeneous.
From this point of view, it has been ascertained that, at present, the forest is going through the dynamic “understorey reinitiation stage” (
This phenomenon, which occurs heterogeneously in the RNI, causes a progressive increase in structural complexity, as it was recently described for the Douglas fir forests in Oregon (
Natural beech-silver fir mixed forests often tend to structural uniformity, at least for a large part of the forests of middle European mountain belt: the phenomenon is related to the capacity of the trees to accumulate biomass. A consequence is the closure of the canopy cover (occurring in different time-lapses, depending on the situation), mainly in the case of forests characterized by competitive tree species such as beech (
As for management aspects of the Apennine silver fir-beech mixed forests located in the middle-mountain belt, according to the results of the present research, shelterwood uniform systems or gap systems covering large patches (> 1000 m2) are not suitable for stands similar to the ones described in the RNI. In the first case, the light microclimate at the forest floor would be altered in favour of beech, in the latter case more light-demanding tree species (mainly
Diameter distribution, separately for each plot and cumulative.
Variation of average HS values in each plot.
Biological spectrum, separately for plot and total (%). (MP): macrofanerofite; (NP): nanofanerofite; (Ch): camefite; (H): hemicriptofite; (G): neofite; (T): terofite (
Form | Plot | Tot | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ||
% | % | % | % | % | % | % | % | % | % | |
MP | 8.00 | 3.77 | 6.06 | 9.09 | 18.52 | 10.87 | 12.77 | 10.00 | 14.29 | 9.26 |
NP | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.35 | 2.13 | 2.50 | 4.76 | 1.85 |
Ch | 4.00 | 1.89 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.50 | 2.38 | 0.93 |
H | 36.00 | 52.83 | 33.33 | 42.42 | 48.15 | 45.65 | 44.68 | 40.00 | 45.24 | 46.30 |
G | 36.00 | 32.08 | 54.55 | 39.39 | 29.63 | 28.26 | 31.91 | 35.00 | 26.19 | 36.11 |
T | 16.00 | 9.43 | 6.06 | 9.09 | 3.70 | 10.87 | 8.51 | 10.00 | 7.14 | 5.56 |
Total | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
Number of trees and basal area (G/ha), separately for plot and tree species (beech and other species).
ADS | n/ha | G/ha | ||||
---|---|---|---|---|---|---|
Beech | Otherspecies | Total | Beech | Otherspecies | Total | |
SF1 | 660 | 110 | 770 | 41.3 | 9.1 | 50.5 |
SF3 | 360 | - | 360 | 50.5 | - | 50.5 |
SF4 | 1330 | 40 | 1370 | 36.7 | 6.3 | 42.9 |
SF5 | 910 | - | 910 | 43.8 | - | 43.8 |
SF8 | 80 | 60 | 140 | 43.9 | 6.4 | 50.3 |
Values for the form parameter
ADS | C |
---|---|
SF1 | 1.5 |
SF3 | 1.4 |
SF4 | 0.8 |
SF5 | 1.2 |
SF8 | 2.1 |
Overall | 0.9 |
Pairwise-comparison between layers as for the number of individuals in each plot (Chi-square test, d.f. = 2). (**): p<0.01.
ADS | SF1 | SF3 | SF4 | SF5 | SF8 |
---|---|---|---|---|---|
SF1 | - | 3.35 | 53.39** | 13.94** | 10.45** |
SF3 | 3.35 | - | 25.36** | 17.4** | 4.86 |
SF4 | 53.39** | 25.36** | - | 59.05** | 36.79** |
SF5 | 13.94** | 17.4** | 59.05** | - | 32.08** |
SF8 | 10.45** | 4.86 | 36.79** | 32.08** | - |
Comparison between layers as for the number of individuals in each plot (Chi-square test, d.f. = 26). (*): p<0.05.
Plot | Value |
---|---|
SF1 | 10.77 |
SF3 | 9.44 |
SF4 | 16.28* |
SF5 | 15.67* |
SF8 | 0.44 |
One way ANOVA for the variable average number of saplings for each sub-plot (60 m2). Variation source: plots.
Origin | d.f. | Variance | F | p-level |
---|---|---|---|---|
Between plots | 4 | 10918.64 | 1.54253 | p<0.01 |
Error | 20 | 707.84 | - | - |
Duncan’s
Plot | Average (n / 60 m2) | Homogeneous groups |
---|---|---|
SF3 | 13 | a |
SF1 | 29 | a |
SF8 | 71 | b |
SF5 | 111 | c |
SF4 | 116 | c |
One way ANOVA for the variable average relative irradiance for each plot. Variation source: plots.
Origin | d.f. | Variance | F | p-level |
---|---|---|---|---|
Between plots | 4 | 0.016553 | 12.5361 | p<0.01 |
Error | 780 | 0.00132 | - | - |
Duncan’s
Plot | Average I.R. | Homogeneous groups |
---|---|---|
SF4 | 0.9% | a |
SF3 | 1.5% | a |
SF5 | 1.7% | ab |
SF8 | 2.4% | b |
SF1 | 3.8% | c |
Appendix 1 - Floristic list, separately for plot, with abundance/dominance indexes according to scale, modified by: (5) cover 80-100%; (4) cover 60-80%; (3) cover 40-60%; (2) cover 20-40%; (1) well represented species, cover from 1% to 20%; (+) species present, but scarce cover (< 1%); (r): sporadic species (1-5 individuals).