http://chameleon.polytechnic.edu.na/wiki/ Sun, 21 Feb 2010 02:25:27 +0200 FeedCreator 1.7.2-ppt DokuWiki http://chameleon.polytechnic.edu.na/wiki/lib/images/favicon.ico http://chameleon.polytechnic.edu.na/wiki/ http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_10 Is there a high incidence of fungal and/or other dieback of Acacia mellifera? Please answer by clicking on one of the following: * Yes(do nothing to the bush and continue with ongoing good management of the grass layer [this could also be considered a decision]) * No. dss Thu, 18 Feb 2010 15:11:59 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_5 Did bush seedlings (if there were some to begin with)or very young saplings survive the Hot Wet Season and Cold Dry Season? Time: End of winter beginning of Hot Dry Season (August to December) Please answer by clicking on one of the following: * Yes * No (go to questions related to ongoing management and treating of Treating of symptoms) dss Thu, 18 Feb 2010 14:57:49 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=seedlings It is difficult to know exactly if what you see is a seedling or a young sapling. This is a healthy seedling. However, if the sapling is only half a centimetre in diameter you could probably treat it as a seedling, although it might be six years old already. Once its lateral roots have developed, it is likely to “behave” differently, and probably becomes more fire resistant. back to question 5 Tue, 03 Nov 2009 16:29:18 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_decision_5 Pull out most surviving seedlings with pliers, or use a hoe to chop them out, and rest the veld for the remainder of the growing season. You should now proceed to Question 9 (questions related to ongoing management and treating of symptoms). Young Acacia mellifera seedlings having germinated. dss Tue, 03 Nov 2009 13:29:51 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_21 Is there a lot of Dichrostachys cinerea amongst the problem bushes? Please answer by clicking on one of the following: * Yes * No Dichrostachys cinerea bushes. Background Dichrostachys cinerea is a strong bush that needs higher concentrations of herbicide to kill it. dss Tue, 03 Nov 2009 12:23:23 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_20 Are there less than 2000 problem bushes per hectare? Please answer by clicking on one of the following: * Yes * No More than 2000 bushes per hectare. Background Bush density influences both the ease of accessing individual bushes and the cost effectiveness of herbicide application. dss Tue, 03 Nov 2009 12:23:00 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_19 ^ Herbicide Application ^ The questions asked from here on relate to herbicide application. The decisions are based upon advice kindly provided by Mr. Van Eck of the Ministry of Agriculture, Water and Forestry, who has decades of experience with herbicide application. The advice of Professor Nico Smit of University of the Free State, is that if herbicides are to be applied to Acacia mellifera, they should only be applied in dry years, when there will be no seed to take over the spaces left by… dss Tue, 03 Nov 2009 12:22:31 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_9 Management of Symptoms The questions asked from this point on relate to decisions regarding “treating the Treating of symptoms” (Decision 8, 9, 10, 19, 20, 21 and 22), and ongoing good preventative management (Decisions 11, 12, 13, 14, 15, 16, 17 and 18). The farmer must use his/her discretion as to when these questions should be asked. Questions related to grass biomass should be asked at the end of the rainy season. Is the cover of bush high enough to sup… dss Tue, 03 Nov 2009 12:19:20 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_4 Are there seedlings present around parent trees and elsewhere? Please answer by clicking on one of the following: * Yes * No (further questions related to ongoing management and treating of Treating of symptoms) A young Acacia mellifera seedling. dss Tue, 03 Nov 2009 12:14:07 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_3 Has there been viable seed production (or is there likely to be, based on the current flowering)? (Time: August to December) Please answer by clicking on one of the following: * Yes * No Acacia mellifera flowering. Flower setting mainly occur during August-September. This is likely to result in high seed production shall quality pods set. dss Tue, 03 Nov 2009 12:13:40 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_2 Was the rainfall of the previous season (just finished) above average? Please answer by clicking on one of the following: * Yes * No Background Research has shown that mature Acacia mellifera in the Highland Savanna mostly produce seeds after a season of exceptionally good rainfall. Similar results were found in the Molopo region in South Africa (Donaldson 1967; Joubert, Rothauge and Smit, in press). In these exceptional rain years, even shrubs of just over 1m can produce Seeds; (Jou… dss Tue, 03 Nov 2009 12:09:04 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_1 What season/time of year is it? Please answer by clicking on one of the following: * End of summer/Beginning of cold dry season * End of winter until the end of hot dry season * Hot wet season Background Different questions would be asked at different times of the year. We can divide the year into 3 Seasons: dss Tue, 03 Nov 2009 12:08:20 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss A Decision Support System for Bush Encroachment by Acacia Mellifera in the Highland Savanna Start NB! Use the DSS for each part of the farm (e.g. per camp). Each part of the farm might be in a different state, or condition, and different decisions might be appropriate. Tue, 03 Nov 2009 12:03:56 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=home Welcome to the Chameleon Bush Encroachment Wiki: a decision tool for farmers. It is an ongoing process to develop this Decision Support System, and thus there may be pages under construction at any time. We greatly encourage you to communicate with us, providing your suggestions for improvement, viewpoints etc. Mon, 02 Nov 2009 15:26:37 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_decision_10 Stem burn selectively. Proceed You have reached a final decision. Back to Chameleon Wiki Home page. If unable to stem burn, then low stocking rate should be applied. Guidelines for recovery periods, if rain continues, are about 90 days on loamy soil and 120 days on sandy soil. Try Decision 9. dss Mon, 16 Mar 2009 17:17:01 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_decision_9 Chop trees and shrubs selectively and apply herbicide to chopped trees and shrub. Proceed If the application of herbicide is considered, then go to Question 19. If unable to chop or apply herbicide, then moderate stocking rate should be applied. Guidelines for recovery periods, if rain continues, are about 70 days on loamy soil and 90 days on sandy soil. Try Decision 10. Otherwise you have reached a final decision. Back to Chameleon Wiki Home page. dss Mon, 16 Mar 2009 17:16:05 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=joubert_rothauge_and_smit_in_prep Citation The correct citation for this reference is * Joubert, D.F., Rothauge, A. and Smit, G.N. 2008. A conceptual model of vegetation dynamics in the semiarid Highland savanna of Namibia, with particular reference to bush thickening by Acacia mellifera. J Arid Environ. 72: 2201-2210. Chameleon Wiki Home Mon, 16 Mar 2009 16:59:58 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=acacia_mellifera2 Acacia mellifera is a fascinating species which in fact is divided into two subspecies: subsp. mellifera and subsp. detinens. The “problem” one is subsp. detinens. In Namibia subsp mellifera is found only near the Kunene River and does not form thickets. More information will be added to this page, as time permits. Below is a typical mature tree, that could be over 100 years old. Patrick Rickert holds a 2m pole and Luke Claassen is measuring the stem circumference. back to home page? Mon, 16 Mar 2009 16:42:26 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_18 Is grass biomass higher than 200gDM/m2? Please answer by clicking on one of the following: * Yes * No [{{dss:fetch18.jpg|] A high perennial grass density and biomass, mostly moribund. Background Biomass of grass that is largely moribund influences the fuel load for burning and the potential for converting to mulch. dss Tue, 18 Nov 2008 09:46:48 +0200 http://chameleon.polytechnic.edu.na/wiki/doku.php?id=dss:dss_question_15 Is grass biomass higher than 200gDM/m2? Please answer by clicking on one of the following: * Yes * No High biomass. Low biomass, perennial grass density of more than one per square metre. Background This question is important because, although you have answered that perennial grass density is high, a low biomass will mean that it has recently been grazed or burnt, thus requiring some rest in the growing season before reuse. dss Tue, 18 Nov 2008 09:45:08 +0200