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Trees and seedlings data of Kakamega and Budongo Forest


Kakamega Forest, Kenya

The mean extrapolated tree number per hectare taking all observatories into consideration was 562 trees with DBH ≥ 10 cm. The average height reached by the trees in the study sites for trees with ≥ 10 cm DBH was 12.4 m in the Camp-site plots and around 20 m in the Colobus and Isecheno sites. The tallest tree in all sites was an Olea capensis with a height of 38.4 m. The tree with the largest DBH of 156 cm was a Zanthoxyllum gilletii. The tree structure with regard to DBH and height distribution appeared to be more or less uniformly distributed (Figs. 1&2) with the exception of one site (Camp). The volume of wood (a cone with the ground diameter and height of a tree) ranged from 12.2 m3 to 106.6 m3 per hectare for the different observatories.

Fig.1 The height distribution of trees ≥ 10 cm DBH in the BIOTA East BDO's in Kakamega Forest is shown. The bars represent the range, the dots the mean with standard deviation. Fig.2 The diameter distribution of trees ≥ 10 cm DBH in the BIOTA East BDO's in Kakamega Forest is presented. The bars represent the range, the dots the mean with standard deviation.




Budongo Forest, Uganda

Mean extrapolated tree number per hectare over all sites was 611 ≥10 cm DBH. The mean tree heigths in the sites ranged from 10.3 m in Waibira 21 (W21) to 13.8 m in N15. The tallest tree over all the sites was a Cynometra alexandri with a measured height of 45.6 m. The tree with the largest DBH was an individual of Alstonia boonei with 224.4 cm. The distribution of the height and DBH per site (Figs. 3 & 4) showed that trees in the nature reserve Nyakafunjo 15 (N15) contain highest values with least found in Nyakafunjo 4 (N4) and W21. Basal areas per hectare for trees ≥5 cm ranged from 19.92 m2 in KP12 to 104.81 m2 in N15. The sites contained 46.57 m2 basal area on average per hectare.

Fig.3 The height distribution of trees ≥10 cm dbh in the BIOTA East BDO's in Budongo Forest is shown. The bars represent the range, the dots the mean with standard deviation. Fig.4 The diameter distribution of trees ≥10 cm dbh in the BIOTA East BDO's in Budongo Forest is presented. The bars represent the range, the dots the mean with standard deviation.


A tree inventory of each of the mentioned BDO's was done in Kakamega and Budongo Forest for trees ≥5 cm DBH in plottripletts (3*400 m2) representing one observatory. The basic structural data are shown. Further mean annual growth rates of the trees ≥10 cm DBH in the respective BDO are presented.
The inventory of the seedling community was done in each observatory in sixteen 4 m2 plots in both forests. Mean annual density, mortality and survival per m2 are listed. Further the diversity indexes for the seedling plots is given for the respective observatory. Additionally litterfall values are presented for the year 2003/04 recorded in three observatories and extrapolated for one hectare.

Abbreviations:
DBH - Diameter at breast height

In each of the mentioned sites three 20 by 20 meter plots for long term measurements were installed in 2001.


Kakamega Forest: Trees ≥5cm DBH


Observatory tree no. per plot triplett mean circumferance
[cm]
basal area
[m2*ha-1]
mean DBH
[cm]
tree per ha mean height
[m]
No. of species
≥ 5cm
per triplett
Shannon Wiener H' Growth rate** 2004
[cm*yr-1]
Growth rate** 2005
[cm*yr-1]
Growth rate** 2006
[cm*yr-1]
Buyangu Hill* 133 63.71 77.30 19.25 1108 14.37 37 4.61 0.79 0.87 0.78
Colobus* 107 66.99 54.46 20.86 892 15.60 31 4.29 0.57 0.57 0.51
SalazarI* 137 48.42 46.01 13.50 1142 12.93 33 4.2 0.70 0.73 0.63
SalazarII* 121 60.74 56.85 17.07 1008 13.43 33 4.52 0.75 0.72 0.71
Camp 184 41.87 22.24 12.74 1533 8.93 29 3.69
Isecheno 89 71.54 83.49 22.77 742 14.16 31 4.45
Kisere 102 57.95 59.72 18.45 850 13.20 22 3.79
Malava 79 55.52 47.09 17.24 658 11.12 29 4
Yala 134 55.97 55.32 17.65 1117 12.75 24 3.58
*Plots with dendrometers measured monthly and seedlingplots measured every three months.   **of trees ≥ 10cm



Kakamega Forest: Seedlings ≤ 100 cm height. Mean annual values for the period from 2002 to 2007


Observatory Mean seedling density per m2 Mean seedling mortality per m2 Mean seedling recruitments per m2 Simpson Index Shannon-Wiener H'
Buyangu Hill* 15.82 1.57 2.15 0.436 1.167
Colobus* 16.85 1.90 2.11 0.872 2.405
SalazarI* 9.12 2.00 2.10 0.746 1.915
SalazarII* 8.39 0.42 0.74 0.752 1.974
Isecheno 3.56 0.16 0.33 0.901 2.481
Kisere 4.61 0.32 0.48 0.869 2.262
Malava 3.50 0.58 0.68 0.767 1.723
Yala 5.72 0.22 0.42 0.868 2.476
*Plots with dendrometers measured monthly and seedlingplots measured every three months.



Budongo Forest: Trees ≥5cm DBH


Observatory tree no. per plot triplett mean circumferance
[cm]
basal area
[m2*ha-1]
mean DBH
[cm]
tree per ha mean height
[m]
No. of species
≥ 5cm
per triplett
Shannon Wiener H' Growth rate** 2006
[cm*yr-1]
W22* 182 43.93 50.62 13.99 1517 11.54 35 4.11 0.47
N15* 158 64.33 104.81 20.48 1092 14.70 18 4.32 0.29
N4* 161 46.46 52.27 14.79 1517 11.22 36 4.16 0.49
W21* 131 37.00 27.95 11.66 1492 10.63 36 4.33 0.40
W36 145 49.79 82.59 15.77 1458 12.69 24 4.52
KP12 164 36.78 19.92 11.67 1225 11.88 21 4.39  
*Plots with dendrometers measured monthly and seedlingplots measured every three months.   **of trees ≥ 10cm



Budongo Forest: Seedlings ≤ 100 cm height. Mean annual values for the period from 2005 to 2007


Observatory Mean seedling density per m2 Mean seedling mortality per m2 Mean seedling recruitments per m2 Simpson Index Shannon-Wiener H'
KP12 5.41 0.24 0.61 0.796 1.863
N15* 7.32 1.21 1.59 0.828 2.072
N4* 2.06 0.20 0.36 0.688 1.438
W21* 4.39 0.27 0.58 0.768 1.839
W22* 5.28 0.32 0.73 0.901 2.540
W36 8.78 0.96 0.96 0.744 1.646
*Plots with dendrometers measured monthly and seedlingplots measured every three months.



Litterfall in Kakamega Forest 2003/04


Observatory t/(ha*yr)
Buyangu Hill 13.35
Colobus 12.88
SalazarI 10.06
Mean 12.10