Forest Health Monitoring In the Ngangao Forest, Taita Hills, Kenya: A Five Year Assessment Of Change

Rogers, Paul C.; O'Connell, Barbara; Mwang''ombe, James; Madoffe, S. S.; Hertel, Gerard

doi:10.2982/0012-8317(2008)97[3:fhmitn]2.0.co;2

Cited by 22 publications

(16 citation statements)

References 9 publications

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“…Although the stem density of trees with diameter at breast height (DBH) greater than 2.5 cm was significantly higher in undisturbed sites than moderately and heavily disturbed sites, the seedling density was higher in the moderately disturbed sites than heavily disturbed sites in Ngangao and Chawia forests. Stand density for trees (DBH > 2.5 cm) for undisturbed, moderately disturbed and heavily disturbed sites in the three forests did not deviate from what was reported in the previous studies (Rogers et al, 2008;Omoro et al, 2010) despite slight differences in the minimum threshold value of DBH used in the studies. Regarding seedling density, Chawia exhibited the highest seedling density for both moderately and heavily disturbed sites than Ngangao.…”

Section: Discussionsupporting

confidence: 43%

Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

Wekesa¹,

Leley²,

Maranga³

et al. 2016

OJF

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The structure and species composition of undisturbed natural forests serve as benchmarks for understanding forest carbon storage potential for reduced carbon emissions. Even though Kenya is seeking to stabilize forest cover, reverse degradation and increase forest cover through mechanisms such as REDD+, there is relatively little information on inherent forest carbon storage potential or its response to disturbance. Comparative studies were undertaken in three remnant fragments of indigenous forests in Taita Hills, Kenya to characterize the structure and forest carbon storage potential of undisturbed, moderately and heavily disturbed sites within these forests. The sensitivity of forest carbon storage estimates to different methods of tree biomass estimation were also examined, including estimates which used DBH, tree height and wood density from extracted tree cores. Disturbance altered the forest structure, reduced species diversity and decreased the capacity of the forests to sequester carbon. The forests' capacity to sequester carbon reduced by between 9.2% and 70.7% depending on the site (forest fragment) and level of disturbance. Models with DBH and wood density gave higher quantities of carbon of between 0.9% and 44.4% for sites exhibiting different levels of disturbance. The present results suggest that disturbance had strong influence on forest structure, species diversity and carbon stocks and therefore maintaining the forests' ecological integrity over the long-term may prove difficult if the frequency and intensity of disturbance increases. Moreover, development and implementation of effective mitigation strategies to reduce carbon emissions will require the use of local biomass models since they are accurate.

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Section: Discussionsupporting

confidence: 43%

Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

Wekesa¹,

Leley²,

Maranga³

et al. 2016

OJF

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“…Forests 2018, 9, 131 3 of 16 We aggregated ecoregion subsection [19] to the level of ecological province due to small sample sizes in some subsections.…”

Section: Study Area and Data Collectionmentioning

confidence: 99%

“…National forest inventories offer an opportunity to use strategic, probabilistic sampling to assess multiple species of concern throughout a wide range of environments [15,16]. The purpose of this study was to quantify four indicators of whitebark pine viability using the US national forest inventory, which represents a spatially representative, broad-scale forest monitoring dataset.…”

Section: Introductionmentioning

confidence: 99%

Pinus albicaulis Engelm. (Whitebark Pine) in Mixed-Species Stands throughout Its US Range: Broad-Scale Indicators of Extent and Recent Decline

Goeking

Izlar

2018

Forests

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Abstract:We used data collected from >1400 plots by a national forest inventory to quantify population-level indicators for a tree species of concern. Whitebark pine (Pinus albicaulis) has recently experienced high mortality throughout its US range, where we assessed the area of land with whitebark pine present, size-class distribution of individual whitebark pine, growth rates, and mortality rates, all with respect to dominant forest type. As of 2016, 51% of all standing whitebark pine trees in the US were dead. Dead whitebark pines outnumbered live ones-and whitebark pine mortality outpaced growth-in all size classes ≥22.8 cm diameter at breast height (DBH), across all forest types. Although whitebark pine occurred across 4.1 million ha in the US, the vast majority of this area (85%) and of the total number of whitebark pine seedlings (72%) fell within forest types other than the whitebark pine type. Standardized growth of whitebark pines was most strongly correlated with the relative basal area of whitebark pine trees (rho = 0.67; p < 0.01), while both standardized growth and mortality were moderately correlated with relative whitebark pine stem density (rho = 0.39 and 0.40; p = 0.031 and p < 0.01, respectively). Neither growth nor mortality were well correlated with total stand basal area, total stem density, or stand mean diameter. The abundance, extent, and relative growth vs. mortality rates of whitebark pine in multiple forest types presents opportunities for management to encourage whitebark pine recruitment in mixed-species stands. The lodgepole pine forest type contained more whitebark pine seedlings (35%) than any other forest type, suggesting that this forest type represents a potential management target for silvicultural treatments that seek to facilitate the recruitment of whitebark pine seedlings into larger size classes. National forest inventories in other countries may use a similar approach to assess species of concern.

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“…There are several methods for analyzing plant diversity and its elements 38,39 , and these methods provide indices which provide bases for comparison. Lou 40 has gone a step further by deriving Effective Numbers from these indices.…”

Section: Diversity Calculationsmentioning

confidence: 99%

“…In many cases such as in the Eastern Arc Mountain forest, the Shannon-Weaver index (H') has been commonly used for these calculations 25,33 . This is because it provides an account of both the abundance and evenness 38 and does not disproportionately favour any species as it counts all the species according to their frequency 39,40 unlike indices such as Simpson's which disproportionately highlights common species (in terms of abundance) instead of showing their frequencies (richness) in samples. One documented disadvantage of the Shannon-Weaver index is however, that it requires a large sample size in order to minimize biases 41 .…”

Section: Diversity Calculationsmentioning

confidence: 99%

Native Tree Species Regeneration and Diversity in the Mountain Cloud Forests of East Africa

Omoro

Luukkanen²

2011

Biodiversity Loss in a Changing Planet

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Forest Health Monitoring In the Ngangao Forest, Taita Hills, Kenya: A Five Year Assessment Of Change

Abstract: This status report presents the results of 43 permanent forest health study plots (3871 trees, saplings,

Cited by 22 publications

References 9 publications

Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

Effects of Forest Disturbance on Vegetation Structure and Above-Ground Carbon in Three Isolated Forest Patches of Taita Hills

Pinus albicaulis Engelm. (Whitebark Pine) in Mixed-Species Stands throughout Its US Range: Broad-Scale Indicators of Extent and Recent Decline

Native Tree Species Regeneration and Diversity in the Mountain Cloud Forests of East Africa

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