In addition to getting the timing right it is also important to pollard at the right height, point on the stem and using the right tools. Pollarding involves cutting the top and branches off of a tree. Normally this is done to promote resprouting at the top of the stem but in the case of our agroforest system we want to allow light into our plot for the cultivation of annual crops or fruit trees. This means that we need to cut the stem at the right height so as to shade the crops below and to give them enough time to grow and be harvested before the branches have regrown to their original length. For this purpose we are aiming to pollard at approximately 1.30 m in height, the height of somebody’s chest.
The best place to cut the stem is a couple of centimetres above or below a branch or branch scar. The reason for this is that new branches will sprout from these points. If you cut through the branch point or scar then the tissue from which new branches will develop will be damaged and new branches will be generated at the nearest point above or below it, meaning that it will be higher or lower than desired. The choice of implement is also important. Whilst it is much quicker and more natural to want to use a machete, this is not the ideal way to cut the branch. The reason for this is that it is hard to get a clean clut with a machete as Inga wood splits very easily and the split wood is vulnerable to insect and fungal infections.
The Inga trees in the first plot that we planted at the end of February 2014 have been big enough to pollard since July. We have not pollarded, however, as the conditions have not been right to do so. As Dr Terry Pennington, Inga agroforest expert explained, you should not pollard trees during the dry season and the best time to do so is a couple of weeks into the wet season. The reason for this is that when you remove all of the leaves and main branches of a tree, the above-ground loss is mirrored below ground. That is the roots die back comensurate with what was lost above. During the dry season there is little water in the soil and the tree needs all its roots to obtain the moisture it needs. Therefore if you have pruned during the dry season, the tree is left without enough roots to survive.
In the case of the Bolivian Amazon, the dry season normally runs from April/May to October/November. This year has been particularly hot and dry, possible a consequence of the El Niño phenomenon, and so pollarding our plot would likely kill all of the trees. We will therefore wait until the middle of November when the rains should have started before pollarding.
At another of our sites, Palacio, the timing of pollarding is also important. The reason for this is that it is a site which floods for a couple of weeks each February. We therefore have to be careful that we leave enough time between pollarding and the floods. Or at least make sure that we pollard high enough so that the new shoots emerge above the floodwaters. So here again the timing of pollarding and the associated planting of crops needs careful thought!
One important task for specialists in a particular plant group, in my case nettles, is to visit national or regional collections and not just rely on the collections of our own institutes, no matter how good they are. As part of a conference and field trip I have just spent a couple of days in the La Paz herbarium. My colleague Nicholas Hind will spend three weeks there identifying plants from the daisy family (Compositae) and running an identification course. There were 92 boxes of unidentified Compositae waiting for him when we arrived!This herbarium was founded by German botanist Stephan Beck in 1984 and currently houses over 400,000 herbarium specimens. The reason why such visits are important both for the specialist but also for the herbarium are that although there is an active inter-herbarium loan system for plants it relies on material being accessioned, mounted and identified. This can be a real challenge to achieve in a country where there are few funds and even fewer botanists. The visit of a specialist allows material that has not been mounted or accessioned, together with unidentified material, to be reliably (one hopes) identified and so used as reference for future identifications. Continue reading Herbarium visit to La Paz (LPB)→
I feel as if I have shed my youth and if I’m honest, early middle-age too, as I leave the Natural History Museum and move to Kew Gardens. I leave with no ill-feeling or sense of regret as I enjoyed over two decades working with some of the most amazing people in one of the great British and scientific institutions. My experiences in the field and working on the collections have made a deep impression on who I am and the science that I try to do, if fitfully and in a slightly uncoordinated manner. I also leave behind several thousand herbarium specimens that hopefully should still be in use a long time after I am no longer around.
But things change, as they should do and always will; the Museum is moving away from taxonomy, the science (& art?) of classification, into more derived collections-based sciences. The emphasis is less on generating new collections and more on synthetic analyses of what they have. It therefore feels like a very natural transition and of course a massive privilege to be moving to the Royal Botanic Gardens, Kew, another great British and scientific institution to continue the eclectic mix of taxonomy, fieldwork and conservation focussed science that have got me this far.
Como parte de nuestros esfuerzos para fortalecer el impacto de nuestro proyecto Futuros Forest hemos sido muy afortunados de asociarnos con la Fundación innocent para expandir nuestro componente agroforestal con una mejor incorporación de árboles frutales. Fondos de la Fundación innocent nos están permitiendo incorporar tres comunidades adicionales, construir viveros de árboles frutales y desarrollar la capacidad dentro de cada comunidad para germinar, crecer y gestionarlos. Como es el caso de las otras acciones de nuestro proyecto comenzamos conversaciones con cada comunidad, atravez del ONG Herencia, sobre cómo esta adición podría encajar en sus planes de desarrollo. También tienen que pensar en qué tipo de frutales quieren producir: la cantidad para consumo personal y para vender. Si sienten que encaje dentro de sus objetivos luego de pasar a la fase más sencillo de construir los viveros y la obtención de semilla.
We believe that the introduction of new approaches to land use needs to be done as part of a broader and integrated plan for a community. It would make little sense for a community to plant an agroforest plot unless they had considered the costs and long-term benefits of doing so. The reason for this is that at several stages in the process there will be challenges and decisions to be taken that will need require the community to remain motivated and able to evaluate the pros and cons of persisting with the system or abandoning it. Given the general lack of success of previous agroforest initiatives elsewhere we feel that this will be the key to our success. As part of our efforts to strengthen the impact of our Forest Futures project and with the support of the innocent Foundation, our main partners Herencia, have been working with three Amazonian communities: Remanzo, Jerico, Monte Sinai, to develop medium to long-term management plans into which agroforest for fruit and annual crops will be integrated.
We established our first Inga agroforest plot just over 17 months ago. Since then the seedlings have grown into 5 m tall trees, their crowns touching and shading out any potential weeds. They have captured the site meaning that it no longer needs any maintenance, allowing farmers to choose when to pollard (prune) at a time that best suits them. In the Bolivian Amazon the best time of year to sow plants is at the beginning of the wet season in October and so we are planning to return to complete this last step in the process.
As part of our efforts to strengthen the impact of our Forest Futures project we have been very lucky to partner with the innocent Foundation to expand our agroforest component and better incorporate fruit trees into them. Funds from the innocent Foundation are enabling us to incorporate three additional communities, build fruit tree nurseries and develop the capacity within each community to germinate, grow and manage them. As is the case for our other Forest Futures actions we start by discussions with each community about how this addition to their community could fit into their development plans. They also need to think about what kind of fruit they want to grow: how much for personal consumption and how much to sell. If they feel that it fits within their long-term goals then we move on to the more straightforward phase of building the nurseries and obtaining seed.
Funded by the Synthesys project I am studying the Cuban nettle collections of the Berlin-Dahlem Museum. The aim is to finish my account of the nettle family for the Flora of Cuba project that I started five years ago. It might seem odd that Cuba has so many nettle species that I can still be working on it, albeit in a fragmented way, for five years. Also that Berlin should be an important repository of Cuban plants, but there is a reason.
Cuba has an exceptionally rich flora and is especially important for the nettle family, Urticaceae, which is represented by about 70 species in eight genera. Together the Greater Antilles, Jamaica, Haiti/Dominican Republic, Cayman Islands and Puerto Rico, is a centre of species-richness for one group of nettles in particular, the genus Pilea. There are over 150 species of Pilea in the Greater Antilles, 60 of which are native to Cuba. The reason for such high diversity is unknown but may have something to do with the age of the islands, preponderance of limestone substrates or something else that we haven’t thought of yet. It does, however mean that I have been spending a lot of time looking at herbarium spcimens of this genus in the Berlin herbarium.
The connection between Germany and the the Greater Antilles started with botanist Ignatz Urban, who did a lot of work documenting the plant diversity of the Greater Antilles. Tragically most of his collections were destroyed in World War Two when the herbarium was bombed. During the Cold War the connection that had established between Berlin and the Caribbean switched to East Germany and the Jena herbarium impulsed by the formidable Johannes Bisse who founded the National Botanic Garden of Cuba. This lead to the foundation of the Flora of Cuba project a collaboration between the many excellent Cuban botanists and their German counterparts, initially in Jena and then from 1993 in Berlin. So that is the reason that I am in Berlin looking at Cuban nettles!
Uno de los elementos más importante de nuestro proyecto es convencer a las comunidades rurales de que los sistemas agroforestales basados en Inga les ayudarán a utilizar sus tierras con mayor intensidad sin necesidad de talar el bosque. Esperamos lograr esto de dos maneras: 1) desarrollar parcelas agroforestales como demostración en una red de comunidades asociadas con el proyecto, y 2) tomar representantes de estas comunidades asociadas para visitar parcelas agroforestales ya productivas. Visitar estas parcelas es una buena manera de dejar que la gente vea por sí misma lo que sus sistemas agroforestales van a lograr en pocos años, y también de facilitar el intercambio de experiencias entre campesinos. Tal vez intercambios entre campesinos tiene más peso/fuerza que hablar con un científico, técnico o una ONG ya que tienen intereses y conocimientos similares/comunes.