"GROWING ALDERS FOR RESTORING HARDKNOTT FOREST" by Angela Sture, Volunteer, October 2021.
On the last work party before Christmas 2020, we were planting oak trees down in the valley on the east side of the river Duddon, hiding from the weather! There was an alder tree still with cones so I collected a pocketful of soggy alder cones with a view to trying to grow some.
According to the (highly recommended) BTCV tree growing handbook it was late for collecting seeds (October/November usually), but when I’d dried the cones out, there were still plenty of seeds dropping out. They were dried and stored over the winter. Advice was to store the dried seeds in a cool, dry place. Some I put some in a plastic bag in the fridge, some were stored in a plastic bag at room temperature.
Pre-treatment was recommended. At the beginning of March, the seed was soaked for 24 hours in cold water and drained. It was mixed with a little moist sand, placed in a loosely tied plastic bag and put in the fridge for 4-6 weeks then sown. What actually happened was slightly different in that when I came to sow the seeds from the fridge 4 weeks later, they were at the back of the fridge and were frozen!
At this point, I also decided to plant some out directly without this pre-treatment, to see what happened and whether pre-treatment was necessary.
So, seeds were soaked on March 2nd, fridged until April 1st (then defrosted!), planted into several pots on April 2nd with peat free compost (Sylvagrow general purpose) with a light covering of compost, watered in and placed outside. By April 25th, there were 11 shoots, all from the pre-treated seeds.
By May 7th, there were 19 seedlings, all from the pre-treated seeds. On June 28th, I transplanted 10 into deep modules and there appeared to be one seedling growing in the untreated seed pot.
In all, I have twenty saplings from the pre-treated seeds and one from the non treated seeds. No significant difference between storing over winter in the fridge or at room temperature.
Conclusion: the pre-treatment worked!
Great experience and look forward to planting them out next year.