Agriculture, Forestry and Fisheries
Volume 4, Issue 3, June 2015, Pages: 138-141

Study on Coppice Management of Acacia nilotica Tree for Better Woody Biomass Production

Abrham Tezera Gessesse*, Tesfaye Teklehaymanot Gezahegn, Hailie Shiferaw Wolle

Amhara Region Agricultural Research Institute, Debre Birhan Agricultural Research Center, Debre Birhan, Ethiopia

Email address:

(A. T. Gessesse)

To cite this article:

Abrham Tezera Gessesse, Tesfaye Teklehaymanot Gezahegn, Hailie Shiferaw Wolle. Study on Coppice Management of Acacia nilotica Tree for Better Woody Biomass Production. Agriculture, Forestry and Fisheries. Vol. 4, No. 3, 2015, pp. 138-141. doi: 10.11648/j.aff.20150403.19


Abstract: Over 90% of the energy consumed in the country is depending on woody biomass. The rising demand for tree products and expanding population pressure resulted in decline of forest cover and consequently the demand for tree products exceeded the supply. This study was conducted at Armania Kebele with the aim of to evaluate different cutting time and management practices yielding more wood biomass volume. One indigenous tree species, preferable by the farmers, namely Acacia nilotica was selected and the experiment design in 3x4 factorial experiment with randomized complete block design arrangement and replicated three wise. Eight trees per plot were planted in two rows with 2 meter spacing. The result shows that, Acacia nilotica could be coppiced well with 13 to 29 numbers of coppices per stump at all stages of cutting time. Root collar diameter and plant height were highly correlated with growth period. Hence, Leaving of two and three number of coppices could give higher woody biomass volumes as compare to leaving one and all number of coppices and control (uncut). Therefore it is necessary that farmers should allow two and three number coppice per stump to get high woody biomass volume for fuel-wood consumption.

Keywords: Acacia, Coppicing, Biomass, nilotica


1. Introduction

The rising demand for tree products and expanding population pressure resulted in the decline of forest cover and consequently the demand for tree products exceeded the supply. The supply of wood and woody biomass products in the north Shewa zone comes from different forest and vegetation types and production systems, including natural forests, woodlands, bush lands, community woodlots, and farm forestry. The share of the total domestic energy is: fuel wood and tree residues 70%, dung 8%, agricultural residues 7% and the rest comes from other sources (EFAP, 1994). Hence, 90% of the total energy is coming from biomass. The trend in north Shewa is not different from the national, especially for the lowlands. According to EFAP, 1994 report a large deficit wood has occurred since 1992 (33 million m3), and fuel-wood deficit amounted to 32.5 million m3. This deficit has been the main cause for the mining of forest resource base. Based on assumed per capita consumption requirements, in 1992 total requirements for wood products have been estimated to be 47.4 million m3, of which fuel wood demand was 45 million m3 (EFAP, 1994). The demand for construction poles and fence posts for construction of new houses and renovation was estimated to be 2.1 million m3. The total deficit is expected to be 84.2 million m3 by the year 2014. Thus, being aware of these deficit alternative sources of energy, afforestation (massive plantation) program and efficient utilization and management of forest land should continue to receive attention based on research results for a greater biomass and quality production.

The existing experience on plantation species in northern Shewa zone indicates that most species used are exotics, dominantly Eucalyptus. There is a danger in overlying on a few species. Pest or disease epidemics could wipe the entire species with devastating effects. This will become serious when there is no alternative species to rely on. Focus has given to exotic species due to the information available and their fast growth rate. However, the indigenous species have been blamed for their slow growth rate. As a general truth,  for most of the indigenous species there is no information at all and  some of the indigenous species are known for their slow growth rate but there are species with fast growth rate, even faster than the exotics.

Study at Sirinka agricultural research centers revealed that Acacia polyacantha produces four times more biomass than Eucalyptus camaldulensis at the end of three years growth (Yigardu 2002). Farmers also indicated their preference to Acacia nilotica for it produces a good charcoal and fuel wood. Moreover, survey report of the center at various weredas indicated that increasing demand for fuel-wood and the decreasing supply trend. The indigenous species which have fast growth rate also have additional desirable attributes over the exotics (e.g. termite resistance/adaptation to the environment). Wood and charcoal sale has been becoming the main stay of some farmers in northern Shewa zone specially when there is food shortage/drought. The accessibility of some weredas to the main road made current and future wood market promising. Though farmers have their own management practices of the above mentioned indigenous species, research efforts made to improve the growth rate/performance through better management is not significant.

Acacia Nilotica occurs in woodlands and scrub in dry and moist kola agro climatic zones, 600-1700 m.a.s.l (Azene Bekele, 2007). It is Medium to fast growing large shrub or small tree, usually 2-6m but can reach 14m, branching from the base to make a rounded crown. Literatures indicate that Acacia nilotica do not coppice well (Tree data base CD, Azene Bekel, 2007,) but farmers in the lowlands of north Shewa say it can coppices well. Therefore, the trial was conducted with the aim of evaluating Acacia nilotica tree species for a greater woody biomass and quality production under different management regimes.

2. Materials and Methods

One indigenous tree species, known for its relative fast growth rate and preferable by the farmers, namely Acacia nilotica was selected for evaluating its coppice potential. The field experiment was conducted at Armania Kebele, Tarma-Ber district, North Shewa zone and the experiment design in 3x4 factorial experiments with randomized complete block design arrangement and replicated three wise. The dimension of a plot was 6.5mx10m (65 m2) and eight trees per plot were planted in two rows with 2 meter spacing. At the age of three years old, four years old and five years old trees were cut close to the ground.  And then after rising of sprouts from the stump Leaving one number of coppice , Leaving two number of coppice , Leaving three number of coppice  and leaving all coppice per stump per cutting time were applied with one satellite control uncut trees. Growth parameters (root collar diameter, height and DBH), survival rate and fresh and dry weight data were collected.

Data Analysis

Data were analyzed using SAS 9.0 followed by least significant difference (LSD) test, was applied for detecting significant differences among means.

3. Result and Discussion

3.1. Root Collar Diameter and Height

The growth parameter result shows that root collar diameter (RCD) and height were increased by R2 98 and 97 percent each month, respectively. The result indicated that root collar diameter and height were highly correlated with growth period (Fig 1 and 2).

NB:- 0=0MAP, 1=3MAP, 2=6MAP, 3=12MAP, 4=15MAP, 5=24MAP, 6=30MAP, 7=36MAP, 8=42MAP, 9=48MAP, 10=54MAP, 11=60MAP, 12=66MAP, 13=72MAP  and 14=78MAP

Fig. 1. Root collar diameter of Acacia nilotica at 36 month after planting

NB:- 0=0MAP, 1=3MAP, 2=6MAP, 3=12MAP, 4=15MAP, 5=24MAP, 6=30MAP, 7=36MAP, 8=42MAP, 9=48MAP, 10=54MAP, 11=60MAP, 12=66MAP, 13=72MAP  and 14=78MAP

Fig. 2. Height of Acacia nilotica at 36 month after planting

3.2. Fresh and Dry Woody Biomass

Fig. 3. Fresh and Dry weight of Acacia nilotica

The result of dry wood biomass of Acacia nilotica ranges from 55 to 58 percent.

3.3. Coppiced Potential and Woody Biomass Volume of Acacia nilotica

The results of this study disproof the previous findings that says Acacia nilotica did not coppice (Tree data base CD, Azene Bekele, 1993,). However, the present study confirmed that Acacia nilotica could be coppiced well at the age of three, four and five years after planting like other coppiced tree species (Chirwa et al, 2003).  From the first cutting time at the age of three years after planting, number of coppice per stump ranges from m 13 to 29 and gave higher volume of woody biomass. The result  of  cutting period and leaving of number of coppice indicates that leaving of two coppices number of Acacia nilotica  could gave higher woody biomass volumes at 36 MAP cutting period as compare to leaving one coppice at 48MAC and  leaving all coppices, three coppices and one coppice at 84 MAP (Table 1).

Table 1. Woody biomass volume comparison of different cutting period and leaving of different number of coppice of Acacia nilotica

Treatment Cutting periods
36MAP 48MAP 60MAP
48MAC m3ha-1 84MAP m3ha-1 36MAC m3ha-1 84MAP m3ha-1 24MAC m3ha-1 84MAP m3ha-1
All coppice 4830a 6190ab 3268ab 6504ab 1688ab 6412ab
One coppice 1412b 3013b 1387b 4518b 380b 5262b
Two coppice 5245a 6316a 5546ab 9982ab 1770a 8657a
Three coppice 3794ab 5327ab 8434a 12172a 1070ab 6993ab
CV 49.46 33.55 51.72 38.65 69.05 21.39

Columns with same letter are not significantly different, MAP (months after plant), MAC (months after cutting) and CV (coefficient of variance).

On the other hand, at 48MAP the result shows that, leave three coppices can harvest 12,172 m3ha-1volume of woody bio-mass and followed by leaving two coppices (9982m3ha1) and all coppices (6504 m3ha-1) than leaving one coppice (4518m3ha-1) at 84MAP. Leaving three, two and all coppices increases the biomass yield by 169%, 120% and 44% respectively as compared to leaving one coppice at 84MAP. The total woody biomass volume obtained at 84 MAP by leaving two and three number of coppices had higher than leaving one coppice.

3.4. Woody Biomass Volume at Coppicing Levels and Cutting Period of Acacia Nilotica

Table 2. Volume comparison of coppicing levels and cutting periods of Acacia nilotica with control

Treatment Total woody bio-mass volume (m3ha-1)
84MAP (36MAP+48 MAC) 84MAP (48MAP+36MAC) 84MAP (60MAP+24 MAC)
All coppice 6190a 6504ab 6412ab
One coppice 3013a 4518b 5262ab
Two coppice 6316a 9982ab 8657a
Three coppice 5327a 12172a 6993ab
Control (Un-cut) 4142a 4142b 4142b
CV 38.24 46.59 33.43

Columns with same letter subscription are not significantly different, MAP (months after plant), MAC (months after cutting), CV (coefficient of variance).

Woody biomass volume comparison of different coppice levels with control (uncut tree) at different cutting period result indicated that there was no significant different among coppice level treatments on woody biomass volume at 84MAP (volume at 36MAP+48MAC) compared to control (Table 2). But higher volume was obtained by leaving two numbers of coppices per stump. The result indicated that, 52% higher woody biomass volume was obtained by leaving two coppices as compare to uncut (control) followed by leaving all and three coppices by 49.4% and 28.6%, respectively.

Leaving three coppices of Acacia nilotica at 48MAP cutting period was obtained significantly higher woody biomass volume than as compare to uncut tree (control) at 84MAP. Leaving three numbers of coppices at 48MAP was gives 12,172 m3ha-1volume of woody biomass which is 193% higher than that of control (un-cut tree). Leaving two and all coppices was also increased woody biomass volume by 140% and 57% per hectoras compare to uncut tree, respectively.

3.5. Woody Biomass Volume at Different Cutting Periods

The result of woody biomass volume at different cutting periods indicated that significant difference was observed among treatments (Table 3). Cutting of Acacia nilotica at 48 MAP and 60 MAP periods was essential and preferable to obtain higher woody biomass volume of tree as compare to uncut tree (Harmer and Howe, 2003). The above two cutting periods could be increase woody biomass volume by 104% and 65%, respectively as compared to uncut.

Table 3. Woody biomass volume at different cutting periods

Treatment Total Woody Biomass Volume at 84MAP (m3ha-1)
36 MAP (Three Years old) 5211bc
48 MAP (Four Years old) 8457a
60 MAP (Five Years Old) 6831ab
84 MAP (Control) 4142c
CV 32.86

Columns with the same letter subscriptions was not significantly different, MAP (months after plant), MAC (months after cutting), CV (coefficient of variance).

3.6. Woody Biomass Volume of Different Coppice Levels

Woody biomass of different coppice levels result indicated that significant difference was observed among treatment (Table 4). Leaving of two and three number of coppices were increased the woody biomass volume of Acacia nilotica by 200.82%, and 197% respectively as compare to uncut tree.

Table 4. Woody biomass volume of different coppice levels 

Treatment Total Woody Biomass Volume at 84MAP (m3ha-1)
All coppice 6352b
One coppice 4264c
Two coppice 8318a
Three coppice 8164ab
Un-cut (Control) 4142c
CV 33

Columns with the same letter subscription was not significant different, MAP (months after plant), MAC (months after cutting), CV (coefficient of variance).

4. Conclusion and Recommendation

Acacia nilotica could be coppiced well and it is a medium to fast growing tree species, at every three months the root collar diameter and height of this tree increased by 1.5cm and 100cm respectively. Therefore, Cutting of Acacia nilotica tree at 36 MAP and 60 MAP with leaving two and three number of coppices gives higher woody biomass volume and increases the woody biomass volume by 270% and by 365% respectively over leaving one number of coppice and control. Despite of the present findings on Acacia nilotica coppice management there is needs to do more research on other ages in order to overcome the problems of fuel wood and other wood demand shortage in the district.


References

  1. Azene Bekele, 2007. Useful trees and shrubs for Ethiopia. Identification, propagation and management for 17 agroclimatic zones. world agroforestry centre, East Africa region, Nairobi, Kenya.
  2. Chirwa, T. S., Mafongoya, P. L. and Chitu, K. 2003. Mixed planted fallow using coppicing and non-coppicing trees for degraded acrisols in Eastern Zambia. Journal of Agroforestry Systems 59(3): 243 – 251
  3. EFAP (Ethiopian forestry action programme), 1994. Ethiopian forestry action program. Volume II. The challenges for development. EFAP secretariat, Addis Ababa, Ethiopia. 
  4. Harmer, R, and Howe, J. 2003. The silviculture and management of coppiced woodlands. Forestry Commission, Edinburgh.
  5. Yigardu, M. 2002. Aboveground Biomass of the Dominant Tree Species on Farmlands in Sirinka Catchment, North Wollo, Ethiopia. MSc thesis, Wondo Genet Collage of Forestry and Swedish University of Agricultural Sciences, Sweden

Article Tools
  Abstract
  PDF(291K)
Follow on us
ADDRESS
Science Publishing Group
548 FASHION AVENUE
NEW YORK, NY 10018
U.S.A.
Tel: (001)347-688-8931