The SPGS inspection and advisory team here lists the most common problems they encounter during their site visits to private planters.
1. Insufficient weed control before planting: Planting trees into a weedy site is a very common practice but is a costly mistake. With Eucalypts, it is essential to fully control the weeds on the site prior to planting and even with Pines, at least the 1m diameter planting pit must be weed free. Many planters are (eventually!) finding out the benefit of pre-plant spraying with glyphosate, particularly where there is heavy grass growth.
2. Poor quality seedlings: many nurseries are still are not culling sufficiently (i.e. sorting and throwing out seedlings that do not make the grade). The optimum seedling size is around 20cm tall – measured from the root collar. Smaller seedlings can be planted but will only succeed where the land preparation and pre-plant weeding has been very good.
3. Seed of dubious origin: ensure the seed has its ‘passport’: you must know (or demand from the supplier) the exact background of the seed to ensure that it complies with the SPGS rules. The SPGS Tree Planting Guideline chapter 5 – Tree Species for Commercial Timber Production in Uganda - has more details.
4. Deformed roots: we are often called to identify the cause tree deaths when they are 1-2 years old. Nine times out of ten this is caused by deformed roots, which indicates a nursery problem. The seedlings could have been pricked out badly (forming the classic ‘J’-shaped root) or they could have been overgrown in the nursery when their roots can easily become ‘pot-bound’ if not pruned regularly.
5. Bad timing of land clearance: often land is being cleared too late leading to insufficient time to burn the trash properly or pre-plant spray. This inevitably leads onto the next problem…
6. Late planting: planting seedlings late in the season is not good practice as it means that very small trees which have not had chance to fully establish their root systems, are then subjected to the hot, dry period following the rainy season. Aim to plant as early as possible in the rains – once the soil is sufficiently moist (to at least 30cm depth) and the rains appear to have settled in.
7. Late beating-up: beating up is the replacement of trees that died after the initial planting and if carried out late, is a major cause of variability in the plantations, with seedlings of very different ages - and thus various sizes - growing together. It is caused often by not raising (or buying) enough seedlings to cover the operation or by planting too late in the first instance. The golden rule with eucalypts is to beat up not more than 4 weeks after initial planting. With pines it is preferable to beat up in the same season. We recommend raising at least 15% extra seedlings for the beating up operation.
8. Labour shortages: if you know labour is in short supply, why not do something about it? For example, invest more in looking after your workers so that they stay with you or train a reliable team for chemical spraying, which saves on manual weeding.
9. Firebreaks: we have seen very few plantations properly protected from fires. As your investment increases and the next season is usually more severe (Dec-Feb), start planning soon to protect your growing assets. Read SPGS Tree Plantating Guideline chapter 16 – Forest Fire Protection.10. Spraying Glyphosate: we have heard stories of nozzles being enlarged (the sprayers were being paid by the knapsack!) and seen for ourselves where unskilled operators caused more harm than good by either not putting sufficient chemical on the target weeds or by damaging the trees through spray drift. The solution? More training and better supervision. Refer SPGS Tree Plantating Guideline chapter 12 – Safe Use of Glyphosate Herbicide