Monday, August 20, 2012

Forest Biotopes in Kundelungu and Upemba

In my last BLOG entitled: Waterfalls, Rapids, Rivers, Streams and Lakes I said there would be more posts to illustrate the key Biotopes that help define the Landscape Ecology  of Kundelungu and Upemba National Parks (see more HERE).   Now, to the third post which focuses on the forest biotopes.


As mentioned in an earlier BLOG entitled:  Landscape Ecology of DAMBOS in Kundelungu we noted that much more is explained by topography and altitude than latitude or longitude in the vegetation sub-types that are observed.  The photo at the left shows the dominant MIOMBO Open Forest on the High Plateau near Lofoi Waterfalls (384 meters high).  Note the Gallery Forest in the canyon.  

Recall that there are THREE ALTITUDE ZONES OF INTEREST to better organize and explain what is seen. 

a) > 1500 meters (cool/cold where more humid savannas and forests are found)

b) 1000 >1500 meters (the mid-plateau valleys/hills with drier forests and savannas and more fire)

c) < 1000 Meters (and the lower valleys and basins where larger lakes, rivers, and wetlands dominate).


Reconsider first of all the LAND CLASSES defined by the  Royal Museum for Central Africa in Tervuren Belgium in their Carte d’Occupation du Sol (see the small version below and larger PDF MAP HERE). 

They identify four classes using the FAO methodology known as the LCCS (Land Cover Classification System; as mentioned earlier that system works fine on a global scale, and if the primary goal is to define forest types by STRUCTURE which is useful for forestry and agriculture applications, e.g. computing biomass or production potentials.  Their land class  categories are:

a) Dense humid forest
b) Flooded/swamp forest (on Hydromorphic soils)
c) Open forest
d) Secondary forest

But, these categories leave out many of the sub-types (Biotopes) that we feel are important for ecological monitoring and research focused on what the park will need to manage.  

So the forest land classes recognized by ecologists and biodiversity experts differ significantly--see the website Biodiversité végétale du Katanga.  Following are the sub-types indicated in each category that they recognize.  These categories are also what the park guards and chiefs recognize though not necessarily by the full technical names.  Therefore, whether these sub-types can all be put on a map (from image analysis) at this time is a little problematic.  It may take longer and is thus something that should/could be postponed until later phases of project implementation in the General Management Plan.  Here are the general classes and sub-types recognized by the biodiversity specialists and botanists:

a) Dense dry forests

The key characteristics of this forest type is that it is a closed canopy, multi-strata forest but less tall than the “humid-Miombo” forest and one more subject to fire.  Furthermore, the emergent layer (tallest trees) lose their leaves in the dry season, and the lower strata can be evergreen shrubs or bush with or without discontinuous tall grasses.  

Two sub-types are defined by the specialists:

1-a more humid version found in western Katanga; it may be in Upemba but I’m not sure yet.  It is dominated by Cryptosepalum exfoliatum and frequently found on Kalahari sandy soils where there is very high rainfall which allows many mosses/ferns to grow profusely in the under-story.  I don't have photos for this type.

2-The dominant dry forest--typical of much of southern Katanga particularly in the Kundelungu and Lubumbashi region and is most evident in the mid-plateau and hills (between 1000>1500 meters altitude).  

Key characteristics include a marked periodicity in litter fall; a few of the tallest trees such as Entandrophragma delevoyi lose their leaves briefly, but most of the vegetation both in the understory and emergent layers is evergreen.  Some of the rather dense understory of shrubs/bushes include Rothmannia whitfieldii , Ritchiea quarrei, Diospyros hoyleana,  and Combretum gossweileri.  Many of these shrubs are denser close to settlements (specialists tell us) and are quite resistant to fire--so they offer some protection to villages from the very common fire risk of the dry season.  

This forest is the primary source for charcoal (Makala) and is under severe pressure as locals degrade the forest via practice of Swidden (Shifting/slash-an-burn) agriculture. Charcoal production is often part of the first phase of clearing.  As the forest gets progressively more degraded it opens up more to a tree-savanna.  Human use of fire is everywhere in the dry season (see photos below).

Above--a photo showing a portion of dry forest being cleared in the first phase of 

Swidden agriculture.  A charcoal production kiln (Makala) is seen and sacks ready for 
pick-up by trucks.Below--a truck picking-up charcoal along the highway as it goes through the 
Dry Forest along the highway corridor along the Kundelungu Escarpment.

Fire burning the dry forest along the Kundelungu Corridor.
Typical Dry Forest along the Highway on the road to Kundelungu that has
not been burned yet.  Note that many trees are still green though
some emergent trees lose their leaves.

b) Dense edaphic forests

These forests and woodlands are established along streams (perennial and intermittent) where soils are deep thus allowing access to groundwater even in the long dry-season when stream flows diminish--there are two sub-types:

1-Gallery forests - the trees often have a large diameter canopy, epiphyes are NOT common, but mushrooms frequent.  Several tree species are common: Khaya nyasica, Phoenix reclinata and  Newtonia buchananii.  Trees with lianas are also frequent such as Mussaenda arcuata or Vanilla polylepis.  Near the waterfalls where there is a lot of spray you often find Platycerium elephantopis.  Along smaller streams or those which are intermittent, the forest becomes more of a “woodland” that is it is a less tall, more DENSE THICKET.  We discussed these forest briefly under AQUATIC SYSTEMS--because access to water is so important.  Recall these photos from Katwe Station in Kundelungu National Park:
The dense Patch Forest (Gallery type) near Katwe Station--see Google Image below
which shows that the gallery forms around the Springs at the headwaters of a stream...
Google Earth Image of Katwe Station in Kundelungu National Park
A gallery forest at Kiubo Lodge along a tributary of the Lufira River.  Note some of the
emergent trees on the ridge that lose their leaves right at the end of the rainy-season--
it produces a type of FALL COLOR that can be quite striking.
Another variation of a gallery forest--in this case along the Lufira River in the
Kundelungu Annex.  Note the dominance of acacia-type trees.
A series of small, dense thickets (riparian woodland) along intermittent streams
in Upemba NP.  In the canyon (top left) the gallery forest is denser because of more moisture

2-Flooded/Swamp Forest - This is a quite rare forest sub-type found almost exclusively where the soil is marshy year-round and the vegetation has special breathing adaptation mechanisms to survive in water-logged soils.   Fire is non-existent in these forests.   Note the example from the Google Earth Image below:

c)  Clear / open forests

This is a mixed forest type which covers about 80-90% of the region.  Its dominant characteristic is that the trees (15-20 meters high) often have light, small leaves; they cover the ground in “umbrella” fashion and they let a lot of light through.  The understory can include grasses but not dense as in true tall grass savanna.  

All the trees and shrubs are HEAVILY FIRE ADAPTED; some plants require fire for germination of seeds which is almost universal in the dry season.  Some trees/shrubs start leafing out in the late dry season after the coldest nights of June/July have passed (in mid-august) even before the rains come.  Other species flower and put out seeds at the end of the rainy season.  So there is a marked rhythm of changing leafing and flowering patterns.  According to biologists, this forest largely replaces the Dense Dry Forest in areas with higher human density and more fire.  In the FAO/LCCS system this forest appears to be classified as either an “open” or “secondary” forest, or “tree savanna”.  This is where the FAO system may not be as useful for park management purposes in Katanga.  


1-Open Miombo Forest--a forest which is very open in the understory with few shrubs/bushes.  A carpet of short green grass covers the ground in rainy season and quickly burns during the dry season without affecting the trees significantly.  There are many other plants in the understory that resprout after fire from bulbs or rhizomes (see photos below) such as Hibiscus rodanthus, Thonningia sanguinea or Sphenostylis. 
Miombo forest in Kundelungu after fire has burned the light understory grasses
Miombo on a steeper slope that suffers from frequent erosion as well as fire;
note below how the plants with bulbs or Rhizomes recover quickly after fire.

2-Miombo dominated by Marquesia macroura--a unique large, beautiful tree specie with heavy “channeled” rough bark.    Biologists claim this forest type is typical of true climax vegetation and is thus in evolutionary terms a key to understanding Miombo forest biology and environmental history.  

The oldest, denser stands are quite beautiful and are quite often of similar age structure and less affected by fire.  They are the true HUMID FORESTS typical of the HIGHEST ELEVATIONS (above 1500 meterswhere large intense fires are less frequent and dry season nights are very cold.  And, it is above the large termite mounds of the lower elevation dry forests. The age and condition of these stands of trees can provide clues to FIRE AND CLIMATE CHANGE HISTORY, i.e. they show the frequency and intensity of fires through their scars (seen in tree-ring analysis) and thus are important biological markers to the past.

3-High Termite Mound Open Dry Forest--this is a unique forest sub-type quite different from the more open Miombo forest or surrounding savannas.  The termite mounds are massive reaching to 8 meters high and 14-15 meters in diameter.  

When not cut for human use, the mounds are covered in a diversity of often spiny, xerophytic plants such as Euphorbia ingens, Begonia princeae var. princeae, etc.  These termite mounds are themselves a specialized ecosystem that can vary significantly by species of termites and presence or absence of other insects.   The termite mounds are not found much above 1500 meters; only the small termite mounds in clayey soils (a type of specialized savanna) are found on the High Plateau of Kundelungu.  See photos below: at the left is a more or less intact termite mound while the one at the right has been degraded by cutting for firewood--the latter was found closer to the urban fringe of Lubumbashi; the third photo shows more degradation and was closer to the city .

A remnant Termite mound near Lubumbashi city limits--the
unique vegetation is almost gone and now the soil is used for brick-making!

Robert (GeoBob) Ford, Rockville, Utah August 20, 2012

1 comment:

  1. it may be in Upemba but I’m not sure yet. It is dominated by Cryptosepalum exfoliatum and frequently found on Kalahari sandy soils evergreen shrubs