Although fast-growing Inga is not the fastest growing plant on a bare site. Several species of grass, vine, tree and shrub, commonly known as ‘pioneer’ species specialise in just such conditions. For the first few months they can outcompete Inga which once over-topped will struggle to grow. Indeed some of the weedy vines are capable of strangling and killing seedlings after only a few weeks. Weeding is therefore essential and if not done can lead to the loss of the site. It is also risky though as it is easy to damage seedlings by mistake and in the case of vines, disentangling them from a seedling, once they have tendrils or suckers firmly attached is a real challenge. Weeding is therefore an onerous and tricky activity. One of our aims to work out how often weeding is required, for how many months, how much effort it requires and how many seedlings we lose as a result. Quantifying such factors will enable us to evaluate how best to minimise the cost and loss from weeding. Currently we are aiming to weed every two months.