Why are my Pine’s needles going yellow and dropping?

Pines drop needles every year, foliage set in previous seasons. It can be quite alarming at first glance with the middle of the plant going yellow to brown before the needles are jettisoned altogether. The sole purpose for a leaf is to harvest sunlight to convert it to food through a process called photosynthesis. Trees grow from the tips so in the case of a Pine, the new foliage created in May through to July shades out the foliage made two seasons prior, rendering this old foliage inefficient and redundant. Once the new season’s foliage is fully functional the tree will discard its older leaves as there is no benefit to put in the resource to maintain them. This transition often happens from September through to December.

You will notice a bed of old needles in a Pine plantation and this is a good example of how this process runs. You don’t notice this transition in older trees so much but in younger trees it can look quite stark. However, nothing to worry about, all part of the tree’s natural process of renewal.

You can read a Pine like a book as it only grows one whorl of growth every year. That’s why it is always the inner part of the plant that is jettisoned. If a Pine goes yellow or starts to die back from its growing tips this is an entirely different and sinister scenario.