Hi all, I’m looking into ways to speed up the planting of indigenous tree seedlings. The soils have a high clay content and the climate is arid regions in Zimbabwe. A minimum soil disturbance method is preferred, instead of digging large holes for each tree seedling. Minimum disturbance is preferred both from a biological perspective, and in terms of time and energy saving. If I were to do a small hole, hardly bigger than the pocket/container the tree seedling is grown, how will this affect my survival rate, are there any studies you know of which have compared these factors? Also, everyone says a square hole is preferable, to prevent root circling. Is this an old wive’s tale, or has anyone actually dug up the roots and compared the growth? I am not having much joy with literature searches. Thoughts?
Agree about min. disturbance - just enough room for the roots. I put more emphasis on: a) addng a bacterial and mycorrhizal inocculant in the pit - for example can soak roots in an inocculant, and/or add a handful of inocculated soil in the pit (e.g. collected from under a parent tree - of the same spp.); b) heavy mulch after planting on the soil around the seedling - with a layer of good compost (again, this can be inocculated) in between the soil surface and the mulch layer. Nature feeds from the top. Think dougnut-shape extending out a good 12-18 inches beyond the stem; c) seedling companion plants (depending whether are any or not) to “nurse” the seedling. In terms of shape of hole, personally I find just a slit is quickest and enough - a spade/spit depth, prized open, insert seedling + innocculant etc. and close the slit, then mulch heavy. Site and context may determine watering needs but if planting in rainy season this may not matter, & mulch will conserve moisture. If on slope, slit better if horizontal across gradient. Then I also like Mark Sheppard’s “STUN” technique - sheer total utter neglect - stick it in and see what survives, they will be the strongest. But out of all the techniques my favourite is do nothing - protect from fire & livestock, and let natural regeneration guide the process. Observe the success/growth rate of nat.regen. compared to planted trees, you won’t be surprised.
I’m in Zimbabwe and I would love to help. I have a firm commitment to the least possible disturbance to the environment and working on a few reforestation and tree planting advocacy work through my community organization called Rima Africa Zimbabwe ( we have a few google hits ). I hope we can be useful to our environment and your initiative.
Beth, we never plant in a hole larger than about 5 inches wide and sometimes as narrow as 1 inch wide and never have a problem having planted maybe 20,000 or more. That includes all sorts of forage trees, fruit trees, etc. If you think about nature, there is no hole. A seed falls to the ground and grows. Best, Glen…in Honduras