Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa

Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies

Survival, growth, stem form and wood basic density of five Pinus Merkusii provenances at Buhindi, Mwanza, Tanzania

Silvae Genetica 47, 2–3 (1998)The performance of 16 Pinus oocarpa (including 5 now reclassified as Pinus patula spp. tecunumanii) provenances at Buhindi Mwanza, Tanzania: is evaluated in terms of survival, height growth, breast height diameter, basal area per ha, wood basic density and stem form. The final assessment was carried out at the age of 22 years. The main results of the study were: – Before angular transformation, survival varied from 77% (Rafael, Nicaragua) to 56% (Conacaste, Guatemala). However no significant difference (P >0.05) in survival was detected after such transformation. – Height growth showed significant differences (P< 0.05) at all ages. At 22 years the outstanding provenances were Siguatepeque (Honduras), Rafael (Nicaragua), and Zamorano (Honduras). Least height growth was shown by Bonete (Nicaragua) provenance. – Significant differences (P< 0.05) were detected in breast height diameter. Outstanding provenances were Yucul, Camelias (Nicaragua) and Mt. Pine Ridge-K49 (Belize). Least performers were Zamorano (Honduras) and Lagulnilla (Guatemala) provenances. – Significant differences (P< 0.05) were detected in basal area per ha development. The Bucaral (Guatemala) provenance was outstanding while least basal area development was recorded in the Conacaste, Lagunilla (Guatemala) and Siguatepeque (Honduras) provenances. – The Bucaral (Guatemala) provenance was significantly superior (P< 0.05) in wood basic density. Least wood basic density values were recorded from Camelias, Yucul, Rafael, Junquillo (Nicaragua), Angeles (Honduras) and the Lagumilla (Guatemala) provenances. – No significant differences (P >0.05) in stem form were observed. It is suggested that the 5 Pinus patula SCHIEDE and DEPPE ssp. tecunumanii (EQUILUZ and PERRY) provenances are likely candidates for species diversification in the Lake Victoria zone where the main plantation species is Pinus caribaea. However, noting that more than half of the natural distribution of P. oocarpa occurs outside central America, more provenances need to be tested to cover that extended range. Similarly, the sparse sampling of P. patula ssp. tecunumanii also needs additional representation. Restricting the results of this study to Pinus oocarpa, provenance ranking in diminishing order of performance gives: Bucaral (Guatemala), Zapotillo, Zamorano (Honduras), Chuacus (Guatemala), Siguatepeque (Honduras), Bonete, Junquillo (Nicaragua), Conacaste (Guatemala), Angeles (Honduras) and San Jose (Guatemala); and Lagunilla (Guatemala). In descending order of performance, suitable Pinus patula ssp. tecunumanii provenances are Mt. Pine Ridge (K49), Mt. Pine Ridge (K29), Rafael, Yucul and Camelias (Nicaragua)

Prevalence and standing volume of Dalbergia Melanoxylon in Coastal and Inland sites of Southern Tanzania

Journal of Tropical Forest Science, Vol. 12, No. 2 (April 2000), pp. 336-347In order to determine the prevalence and standing volume of Dalbergia melanoxylon( mpingo), 120 sample plots were laid out in each of two districts, Kilwa and Nachingwea, representing coastal and inland woodlands in Lindi Region, southern Tanzania. Using data from felled trees, volume equations for various utilisation classes were constructed. Also estimated were the basic density of mpingo, the percentage content Of heartwood, sapwood, and heartrot, and the thickness of bark and sapwood.The basic density values for mpingo were 1.14,0.76 and 1.06 g cm' for heartwood, sapwood, and both heartwood and sapwood. These are multiplier factors to obtain biomass values from volume. The heartwood content of mpingo is 83% of the total volume and the rest (17%) is sapwood and bark. Based on a few logs observed 13% of the total volume may be expected to have heartrot. The sapwood thickness is 1.1 cm with little variation irrespective of log diameter. The bark is thin (3.7 mm) and soft making the tree susceptible to damage by bruising and fire.The inland forests have twice as much overbark volume of mpingo as the coastal forests with 10 and 5 m3 ha"1 respectively. The merchantable volume to 20 cm top diameter overbark is 4.4 and 1.7 m3 ha"1 accounting for only 43 and 33% of the total volume per hectare respectively. Since regeneration of mpingo is easy, there is no immediate need to classify mpingo as an endangered species provided fire control is enhanced as an important conservation measure. It is, however, appropriate to regard the species as threatened

Survival, growth and wood density of Pinus Kesiya provenances at Buhindi, Mwanza, Tanzania

Journal of Tropical Forest Science, Vol. 11, No. 2 (April 1999), pp. 401-409he objective of this study was to evaluate the performance of 13 Pinus hesiya provenances at Buhindi, Mwanza, Tanzania. Periodic data were collected on survival, breast height diameter and height. A final assessment was carried out at 18.3 y for survival, breast height diameter, height, stem form and basic density. Except for wood basic density, all other variables differed significantly (p<0.05) between provenances. The following provenances with satisfactory performance are recommended for small-scale planting at Buhindi: Benguet Kabayan and Zambale

Prevalence and standing volume of Dalbergia Melanoxylon in Coastal and Inland sites of Southern Tanzania

Journal of Tropical Forest Science, Vol. 12, No. 2 (April 2000), pp. 336-347In order to determine the prevalence and standing volume of Dalbergia melanoxylon( mpingo), 120 sample plots were laid out in each of two districts, Kilwa and Nachingwea, representing coastal and inland woodlands in Lindi Region, southern Tanzania. Using data from felled trees, volume equations for various utilisation classes were constructed. Also estimated were the basic density of mpingo, the percentage content Of heartwood, sapwood, and heartrot, and the thickness of bark and sapwood.The basic density values for mpingo were 1.14,0.76 and 1.06 g cm' for heartwood, sapwood, and both heartwood and sapwood. These are multiplier factors to obtain biomass values from volume. The heartwood content of mpingo is 83% of the total volume and the rest (17%) is sapwood and bark. Based on a few logs observed 13% of the total volume may be expected to have heartrot. The sapwood thickness is 1.1 cm with little variation irrespective of log diameter. The bark is thin (3.7 mm) and soft making the tree susceptible to damage by bruising and fire.The inland forests have twice as much overbark volume of mpingo as the coastal forests with 10 and 5 m3 ha"1 respectively. The merchantable volume to 20 cm top diameter overbark is 4.4 and 1.7 m3 ha"1 accounting for only 43 and 33% of the total volume per hectare respectively. Since regeneration of mpingo is easy, there is no immediate need to classify mpingo as an endangered species provided fire control is enhanced as an important conservation measure. It is, however, appropriate to regard the species as threatened

Survival, growth and wood density of Pinus Kesiya provenances at Buhindi, Mwanza, Tanzania

Journal of Tropical Forest Science, Vol. 11, No. 2 (April 1999), pp. 401-409he objective of this study was to evaluate the performance of 13 Pinus hesiya provenances at Buhindi, Mwanza, Tanzania. Periodic data were collected on survival, breast height diameter and height. A final assessment was carried out at 18.3 y for survival, breast height diameter, height, stem form and basic density. Except for wood basic density, all other variables differed significantly (p<0.05) between provenances. The following provenances with satisfactory performance are recommended for small-scale planting at Buhindi: Benguet Kabayan and Zambale

Survival, growth, stem form and wood basic density of five Pinus Merkusii provenances at Buhindi, Mwanza, Tanzania

Silvae Genetica 47, 2–3 (1998)The performance of 16 Pinus oocarpa (including 5 now reclassified as Pinus patula spp. tecunumanii) provenances at Buhindi Mwanza, Tanzania: is evaluated in terms of survival, height growth, breast height diameter, basal area per ha, wood basic density and stem form. The final assessment was carried out at the age of 22 years. The main results of the study were: – Before angular transformation, survival varied from 77% (Rafael, Nicaragua) to 56% (Conacaste, Guatemala). However no significant difference (P >0.05) in survival was detected after such transformation. – Height growth showed significant differences (P< 0.05) at all ages. At 22 years the outstanding provenances were Siguatepeque (Honduras), Rafael (Nicaragua), and Zamorano (Honduras). Least height growth was shown by Bonete (Nicaragua) provenance. – Significant differences (P< 0.05) were detected in breast height diameter. Outstanding provenances were Yucul, Camelias (Nicaragua) and Mt. Pine Ridge-K49 (Belize). Least performers were Zamorano (Honduras) and Lagulnilla (Guatemala) provenances. – Significant differences (P< 0.05) were detected in basal area per ha development. The Bucaral (Guatemala) provenance was outstanding while least basal area development was recorded in the Conacaste, Lagunilla (Guatemala) and Siguatepeque (Honduras) provenances. – The Bucaral (Guatemala) provenance was significantly superior (P< 0.05) in wood basic density. Least wood basic density values were recorded from Camelias, Yucul, Rafael, Junquillo (Nicaragua), Angeles (Honduras) and the Lagumilla (Guatemala) provenances. – No significant differences (P >0.05) in stem form were observed. It is suggested that the 5 Pinus patula SCHIEDE and DEPPE ssp. tecunumanii (EQUILUZ and PERRY) provenances are likely candidates for species diversification in the Lake Victoria zone where the main plantation species is Pinus caribaea. However, noting that more than half of the natural distribution of P. oocarpa occurs outside central America, more provenances need to be tested to cover that extended range. Similarly, the sparse sampling of P. patula ssp. tecunumanii also needs additional representation. Restricting the results of this study to Pinus oocarpa, provenance ranking in diminishing order of performance gives: Bucaral (Guatemala), Zapotillo, Zamorano (Honduras), Chuacus (Guatemala), Siguatepeque (Honduras), Bonete, Junquillo (Nicaragua), Conacaste (Guatemala), Angeles (Honduras) and San Jose (Guatemala); and Lagunilla (Guatemala). In descending order of performance, suitable Pinus patula ssp. tecunumanii provenances are Mt. Pine Ridge (K49), Mt. Pine Ridge (K29), Rafael, Yucul and Camelias (Nicaragua)

Using satellite radar backscatter to predict above-ground woody biomass: A consistent relationship across four different African landscapes

Regional-scale above-ground biomass (AGB) estimates of tropical savannas and woodlands are highly uncertain, despite their global importance for ecosystems services and as carbon stores. In response, we collated field inventory data from 253 plots at four study sites in Cameroon, Uganda and Mozambique, and examined the relationships between field-measured AGB and cross-polarized radar backscatter values derived from ALOS PALSAR, an L-band satellite sensor. The relationships were highly significant, similar among sites, and displayed high prediction accuracies up to 150 Mg ha−1 (±∼20%). AGB predictions for any given site obtained using equations derived from data from only the other three sites generated only small increases in error. The results suggest that a widely applicable general relationship exists between AGB and L-band backscatter for lower-biomass tropical woody vegetation. This relationship allows regional-scale AGB estimation, required for example by planned REDD (Reducing Emissions from Deforestation and Degradation) schemes