Seed collection methods and systems
Mike Phillips, a former research head forester at Newton, published several papers during his career and in retirement. In the attached PDF which includes several papers, Mike has looked at the issues surrounding seed collection, assessment and harvesting methods as well as considerations on maintaining good genetic diversity.
Mike writes:
‘Before 1950 little attention was paid to the quality or origin of the parent stand before making forest tree seed collections. As a result it is highly probable that the poor performance of many of our middle- aged crops can be directly related to one of these factors.
Furthermore the most prolific cone-bearing trees with easily accessible cone crops were commonly sought by seed collectors. Whenever possible, collections were made from the ground and still are and it is on the lower branches of trees that the highest incidence of self-pollination takes place; this sometimes results in low seed germination and plants with slow rates-of-growth and undesirable stem form.
This article provides guidelines to foresters wishing to decide whether or not to embark on commercial coniferous forest tree seed collections and, secondly, discusses methods that they can use in harvesting them’.
Mike also gives a little insight into historical seed collections of commoner conifer species as below:
‘Sitka spruce
Between 1921 and 1955 over 14000kg of seed, approximately 80% of all the imported Sitka spruce seed, came from the Queen Charlotte Islands in British Columbia - an origin which has produced planting stock well-suited for most British needs.
The large importations have undoubtedly provided foresters in Britain with a sound genetic base for future commercial seed collections. Even assuming 100gm of seed per parent tree, the base population in the Queen Charlotte Islands must have been in the order of tens of thousands of trees’.
And again on genetic diversity:
‘In any scheme or plan to establish native plants, seed is usually the basic entity and procuring it is of prime importance. This should take account of the prevailing ecological and biological situation and ensure that a broad cross section of the population is sampled to provide adequate genetic diversity’.
See the PDF above for full version of the papers.
Groups: Forest Research, Forestry Records, Booklets and Reports