Volume 22(3), 73- 78, 2018 JOURNAL of Horticulture, Forestry and Biotechnology

www.journal-hfb.usab-tm.ro

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Evolution of standing volumes by species in the Lipova Hills region using the Romanian National Forest Inventory’s methodology Dancea I. D.1*, Turcu D. O.1, Marin G.2

1National Research and Development Institute for Forestry “Marin Drăcea” – Timişoara branch;

2National

Research and Development Institute for Forestry “Marin Drăcea” *Corresponding author. E-mail: danceaion@yahoo.com Abstract The Lipova Hills region, located in Western Romania, is well covered by forests. The forest ecosystems are highly diverse regarding the tree species, about 25 different species being present in the upper canopy of the forests. Although most of the area is covered by mixed Quercus forests, in the Eastern part of the territory the European beech becomes more dominant. This study aims to roughly estimate the evolution of the standing volumes by tree species within the three Forest Districts from the region – Bârzava, Radna, Săvârșin – using the methodology and sample data from the Romanian National Forest Inventory (IFN). Within the first cycle of measurements (2007-2012), the mean volumes per hectare were respectively 371.653 m

3/ha for Bârzava Forest District, 256.865 m

3/ha for Radna and

332.709 m3/ha for Săvârșin. The values for the second cycle (2013-2018)

were respectively 374.212 m3/ha – Bârzava, 271.277 m

3/ha – Radna and

348.765 m3/ha – Săvârșin. The close similarity between the values from the

first cycle of inventory and the second cycle suggests a high stability of the forest ecosystems.

Key words Standing volumes, Lipova Hills, Romanian National Forest Inventory

The Romanian National Forest Inventory (IFN) was

established in Romania in 2006 (roifn.ro) as part of the

country’s accession to the European Union. The IFN is

an inventory based on modern methodologies and has

multiple aims: to evaluate the forest resources of the

country, to generate information for developing forest

policies, to generate information about the carbon

storage in the forest ecosystems and reporting under

the Kyoto Protocol, to gather information about the

biological diversity of the forests, etc. (roifn.ro).

The older forest inventories of Romania were

accomplished in the respective years 1973, 1980, 1984

using the information gathered by the forest

management planning system, without specific field

measurements. The modern IFN, established more than

a decade ago, continuously gathers information based

on a grid of sample plots; the first cycle of the

inventory was (2007) 2008-2012, and the second cycle

(2013-2018) will be completed at the end of 2018

(roifn.ro).

We used the data collected by the National Forest

Inventory, from 34 sample plots established in three

Forest Districts (Bârzava, Radna, Săvârșin) from the

Lipova Hills region. The raw information from IFN,

from both measurements (cycle I and II), was used

independently for calculations in order to express the

evolution of standing volume per hectare and by

species in the chosen region.

Material and Method

The National Forest Inventory uses permanent sample

plots (each of them with 4 sub-plots, Fig. 1.) which are

fully measured within a cycle of 5 years (*** 2007,

2013). The Inventory statistically covers the territory of

the country following a 4 x 4 km grid network in the

areas where the forest are well represented and 2 x 2

km in the areas where forests are rather scarce

(roifn.ro) (*** 2007, 2013).

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Fig. 1. The sample plot consisting of 4 sub-plots (roifn.ro)

Our study focuses on the hilly region in the nearby of

Lipova Town, Western Romania, on the Northern side

of the Mureș River (Fig. 2.), in the lowest part of its

basin, before its arrival in the Western Plains. This

hilly region’s specificity consists of oak forests which

are transiting to the East in beech dominated forests,

having a diversified range of species (taxons) which

establishes high biodiversity values.

Fig. 2. Study site – the Lipova Hills region (earth.google.com)

We used 34 sample plots (with 114 sub-plots) from the

National Forest Inventory, which cover the area of

three forest districts: Bârzava, Radna, Săvârșin. For all

trees (starting from diameter at breast height of 56 mm)

their respective positioning was recorded – polar

coordinates from the sub-plot center, then the

diameters at breast height (DBH, at 1.3 m) were

measured and recorded, total heights (H) were

measured using Vertex III device with high precision

(0.1 m) and recorded. All these measurements, together

with other measurements and qualitative information

about trees were recorded in the field in the specific

IFN software (roifn.ro).

The standing volume was calculated by aggregating the

individual volumes of all trees, which respectively

were computed using the following formula (Giurgiu et

Decei 1997):

log(v) = a0 + a1 log d + a2 log2 d + a3 log h +

a4 log2h

Where: v represents the individual volume of the tree

in m3, d represents the diameter at breast height in cm

and h represents the total height of the tree in m.

The parameters of the equation for the species found in

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our sample plots are shown in Table 1 (Giurgiu et Decei 1997):

Table 1

Parameters of the volume equation (Giurgiu et Decei 1997)

Species a0 a1 a2 a3 a4

Acer campestre -3.22096 1.58409 0.13567 -0.08677 0.313054

Acer platanoides -3.48668 1.00128 0.40669 0.74812 -0.013734

Acer pseudoplatanus -4.06012 1.81478 0.07283 0.76688 0.006155

Acer tataricum -3.45646 1.94746 0.01879 -0.16420 0.342355

Betula pendula -4.16999 2.27038 -0.21540 0.30765 0.368258

Carpinus betulus -4.23139 2.15204 -0.00988 0.59652 0.112810

Cornus mas -3.22096 1.58409 0.13567 -0.08677 0.313054

Corylus avellana -3.22096 1.58409 0.13567 -0.08677 0.313054

Crataegus sp. -3.45646 1.94746 0.01879 -0.16420 0.342355

Fagus sylvatica -4.11122 1.30216 0.23636 1.26562 -0.079661

Fraxinus excelsior -3.53048 1.26636 0.31105 0.52368 0.082743

Fraxinus ornus -3.53048 1.26636 0.31105 0.52368 0.082743

Malus sylvestris -3.50736 1.91195 0.02764 -0.28831 0.432403

Picea abies -4.18161 2.08131 -0.11819 0.70119 0.148181

Pinus nigra -4.01698 1.96342 0.01241 0.57848 0.094783

Pinus strobus -4.36966 1.55475 0.14981 1.40295 -0.157352

Pinus sylvestris -3.84672 1.82103 -0.04107 0.35677 0.334910

Populus tremula -4.22131 1.76256 0.05900 1.04105 -0.009430

Prunus avium -3.59371 1.95047 0.04086 -0.12835 0.374948

Prunus domestica -3.59371 1.95047 0.04086 -0.12835 0.374948

Pseudotsuga menziesii -4.29910 1.90710 0.02841 1.01819 -0.055894

Pyrus pyraster -3.96965 2.11784 -0.03021 0.32199 0.127335

Quercus cerris -3.68707 2.03534 -0.06747 -0.15871 0.500372

Quercus frainetto -4.25185 2.03370 -0.02026 0.93727 -0.022033

Quercus petraea -4.17315 2.27662 -0.09084 0.57596 0.093429

Quercus robur -4.13329 1.88001 0.04880 0.95371 0.063638

Quercus rubra -3.60162 2.03988 0.00783 -0.13348 0.337740

Robinia pseudoacacia -3.37551 1.80802 0.02827 -0.33554 0.512150

Salix alba (vegetative regeneration) -4.19326 1.58473 0.01938 0.93588 0.144451

Salix caprea -4.01470 1.72202 0.08639 0.85987 -0.009759

Sambucus nigra -3.22096 1.58409 0.13567 -0.08677 0.313054

Sorbus domestica -4.31485 2.58064 -0.21693 0.55092 0.025773

Sorbus torminalis -4.31485 2.58064 -0.21693 0.55092 0.025773

Tilia sp. -4.80605 1.92424 0.02214 1.96408 -0.452969

Ulmus sp. -4.49118 2.18244 -0.10324 1.20293 -0.124978

Results and discussions

The total number of trees measured for the 34 sample

plots within the first cycle of IFN was 3246 (by Forest

District, repectively: Bârzava 826, Radna 965, Săvârșin

1455 trees). Within the second cycle of IFN, the total

number of trees measured was 3027 (respectively:

Bârzava 793, Radna 875, Săvârșin 1359 trees). The

new trees recorded for the second cycle are 179

(Bârzava 49, Radna 53, Săvârșin 77 trees). During the

5 years interval between the two recording cycles, a

total number of 398 trees were lost (Bârzava 82, Radna

143, Săvârșin 173 trees) due to multiple causes: natural

elimination of some trees due to competition, normal

tree harvesting, tree break under 1.3 m, in rare cases

some trees were not accesible in the firts cycle, also in

rare cases some trees were not inside the plot any more

(horizontal distance from the sub-plot center to the tree

is larger than the sub-plot radius, mainly caused by

landslides). The volume gain through the “new” trees

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is respectively 5.351 m3/ha for Bârzava Forest District,

6.945 m3/ha for Radna and 5.468 m

3/ha for Săvârșin.

The volume “lost” by dissapearance/cutting of trees is

represented respectively by: 2.792 m3/ha for Bârzava, -

7.466 m3/ha for Radna and -10.587 m

3/ha for Săvârșin,

the last two negative values meaning that actually the

volume extracted/dissapeared is more than the

increment of the standing trees combined with the

volume gained by the “new” trees.

The mean standing volume per hectare for the studied

area for the first cycle was 320.409 m3/ha. For the

second cycle the average standing volume is 331.418

m3/ha, increasing by a rate of 3.44% compared to the

first cycle. By Forest District, the average standing

volume is 371.653 m3/ha for Bârzava for cycle I and

374.212 m3/ha for cycle II (increasing by 0.69 %); in

Radna, cycle I totalizes 256.865 m3/ha and cycle II

totalizes 271.277 m3/ha (increasing by 5.61 %); in

Săvârșin, the mean of cycle I is 332.709 m3/ha and the

mean of cycle II is 348.765 m3/ha (increasing by 4.83

%) (Fig. 3).

Fig. 3. Evolution of total standing volume per hectare, Cycle I and Cycle II

The evolution of standing volumes by species within the three Forest Districts is shown in Fig. 4, Fig. 5, Fig. 6:

Fig. 4. Evolution of standing volume per hectare by species, Bârzava Forest District

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The evolution of the standing volume per hectare in the

Bârzava Forest District shows a slight increment, if we

consider all the species (0.69 %) (Fig. 4.). At

individual species though, there are strong relative

increments – Salix alba by 42.69 %, Tilia sp. by 36.03

%, Pyrus pyraster by 33.53 %. There are also strong

relative decreases – Quercus robur by 100 %, Fagus

sylvatica 28.92 %, Populus tremula 21.9 %. Other

species, like Quercus petraea, showed a very small

evolution between the two cycles of the Inventory.

Fig. 5. Evolution of standing volume per hectare by species, Radna Forest District

Within the Radna Forest District, the evolution of the

standing volume per hectare shows an increment of

5.61 %, considering all species (Fig. 5.). The highest

positive evolution is represented by the following

species: Fagus sylvatica – 49.71 %, Sorbus domestica

– 41.12 % and Pyrus pyraster – 32.94 %. The relative

decreases are lead by Acer campestre – 69.14 %,

followed by Salix caprea – 67.47 % and Robinia

pseudoacacia – 36.91 %. Quercus petraea and

Quercus frainetto have shown a relative constance in

volume through the two cycles of the Inventory.

Fig. 6. Evolution of standing volume per hectare by species, Săvârșin Forest District

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The standing volume of the forests from the Săvârșin

Forest District show a small tendency of increasing

between the two cycles of the IFN (4.83 %) (Fig. 6.).

The positive evolution tendency is lead by Sambucus

nigra – 172.25 %, followed by Fraxinus ornus– 61.41

% and Robinia pseudoacacia – 42.14 %. The relatively

negative tendency is shown by the following species:

Corylus avellana – 92.36 %, Salix caprea and Acer

tataricum – both with 100 %. Fagus sylvatica, which

becomes one of the dominant species in this area,

shows a remarcable constance tendency (1.52 %

increment).

Conclusions

The mean standing volume per hectare (considering all

three Forest Districts) was 320.409 m3/ha for the first

IFN cycle, very close to the national average standing

volume per hectare which is 321.925 m3/ha (roifn.ro),

while for the second cycle was 331.418 m3/ha

(increasing by 3.44%). The evolution of standing

volume for all of the three studied Forest Disticts

showed a light increasing tendency, respectively

Bârzava by 0.69 %, Radna by 5.61 % and Săvârșin by

4.83 %.

The evolution of the standing volume per hectare by

species shows great increases in Salix alba, Tilia sp.

and Pyrus pyraster in Bârzava Forest District, Fagus

sylvatica, Sorbus domestica and Pyrus pyraster in

Radna Forest District and Sambucus nigra, Fraxinus

ornus and Robinia pseudoacacia in Săvârșin Forest

District. On the other hand, some species show great

volume decreases between the two cycles, like Quercus

robur, Fagus sylvatica and Populus tremula in Bârzava

Forest District, Acer campestre, Salix caprea and

Robinia pseudoacacia in Radna Forest District and

Acer tataricum, Salix caprea and Corylus avellana in

Săvârșin Forest District. Some species show a

remarcable constance in volume, like Quercus petraea

in Bârzava Forest District, Quercus petraea and

Quercus frainetto in Radna Forest District and Fagus

sylvatica in Săvârșin Forest District.

The evolution of standing volumes by species, studied

within the three Forest Districts, leads to the

conclusion that from West towards East, the

importance of the oak species decreases and the beech

is more and more dominating. The high stability of the

studied forest ecosystems is indicated by the close

similarity between the observed standing volumes from

the first cycle of inventory and the ones from the

second cycle.

Acknowledgements

The author D. O. Turcu was supported by the project

PN 18040401.

References

1. Giurgiu, V.; Decei, I., 1997: Biometria arborilor din

România. Metode dendrometrice / Biometry of the

trees in Romania. Dendromethrical methods, Editura

Snagov, București, 307 p.

2. ***, 2007: Instrucțiuni pentru culegerea datelor de

teren pentru Inventarul Forestier Național, Inventar

pilot, uz intern, Institutul de Cercetări și Amenajări

Silvice, Serviciul Inventar Forestier Național, 99 p.

3. ***, 2013: Inventarul Forestier Național, Instrucțiuni

pentru lucrările de teren, IFN2, 2013-2018, Ediția a II-

a, uz intern, Institutul de Cercetări și Amenajări

Silvice, Serviciul Inventar Forestier Național, 94 p.

4. www.earth.google.com

5. www.roifn.ro