Notes and Thoughts on Apple Pruning Paper

Disclaimer: Scientific papers can, at times, be exceptionally hard work decoding their practical value. That is why I take notes on papers for future reviewing and understanding without having to return to the original texts. These notes are provided purely as a service to others and of my community while I do studying myself. The following notes may appear to be raw (because they are), and there is no expressed warranty regarding them. Following the notes are personal thoughts at the time of the reading, provided first as a service to myself, then also as a service to others. These too may appear to be raw and unpolished (because they are).

How young trees cope with removal of whole or parts of shoots: An analysis of local and distant responses to pruning in 1-year-old apple (Malus ×domestica; Rosaceae) trees

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Notes

  • Two types of prunings conducted on 1 year old apple trees that were then examined after 2-3 years of growth.
    • Heading
    • Thinning
  • Each tree started as a multi-limbed tree, although no limbs had side branching
  • 5 Tree Tests Performed. All tests used the same pruning technique in summer as they did in the following winter.
    • Control – No pruning at all.
      • After first pruning:
        • Longer limbs
        • Side branching on limbs
      • After second pruning:
        • Some longer limbs, not as much.
        • Much More side branching
        • Occasional new “limb” produced on 1st limbs.
    • Heading Cut performed half way down tree
      • After first pruning:
        • The cut area produced NEW buds and grew a multi-trunked top with one ever so slightly taller
        • Longer limbs
        • NO side branching on limbs
      • After second pruning
        • Main limbs grew longer than control
    • Heading Cuts performed half way (or more) down side shoots
      • After first pruning:
        • Buds near cuts grew longer in a slightly different direction
        • Not as long as the control or the single heading cut.
      • After second pruning:
        • Main limbs grew longer than control
    • Thinning Cut performed on 50% of all lateral shoots (branches)
      • After first pruning:
        • Where unpruned limbs existed, they grew longer.
        • Pruned areas grew back, only slightly.
        • NO side branching on limbs
      • After Second Pruning
        • More growth and side branching occuring on now larger limbs
    • Thinning Cut performed on 100% of all lateral shoots
      • After first pruning:
        • Grew back in the pruned locations but shorter in length.
        • NO side branching on limbs.
      • After second pruning
        • Cut growth returned by about 3/4
  • Conclusion Section
    • Earlier summer pruning likely maintains root and top growth balance, vs pruning at the end of summer.
      • Was shown that there was no invigorating effects seen a second year, unlike the trials conducted here. (Via winter pruning)
    • Competition may have been occurring between vegetative and flowering components. Floral differentiation was not occuring in autumn as was expected. Instead vegetative growth was occurring.
    • When thinning cuts were performed the main trunk remained a smaller diameter leading them to believe it was from new shoot formation draining resources.
    • Branches are not independent entities from the overall tree as seen from the growth effects stimulated by pruning far from where it occurred.
    • Possible that thinning cuts delay developmental processes, due to plant focusing on replenishing limbs.

Thoughts

  • Does summer prunings that are composted in place, or go through the gut of an animal produce an ecology that keeps plant decay tidy and clean, possibly taking residence where “diseases” might otherwise?
  • Winter pruning likely removes minimal if any life force from the tree as it is being stored in the roots. When the tree is bursting forth with new growth its sucking in the roots’ energy and sending it out the top.
  • Thinning cuts seem to remove the most amount of will from the plant to branch and fruit.
  • Heading cuts on the overall tree do not seem to impact negatively the lower branches, only forcing the creation of new shoots in the center competing for the top.
  • This may validate Dave Wilson’s techniques of backyard fruit culture, that really keeping the top canopy down in summer will keep a tree in check, but still allowing it to develop.
  • Thinning cuts appear to actually be effective at thinning out inner branches, but very ineffective for keeping height in check.
  • Heading cuts appear to be effective at diffusing energy from a single stem into multiple. At the right times (early summer and later summer) this likely slows down the race for size of the plant.
    • Note: Heading cuts are specifically cuts where any specific length of a plant is cut by at least half. The cut, really heads it back.
    • This diffusion of energy makes the plant more bush like.