Eucalyptus seed.

 Eucalyptus seed.

There are over 600 species of Eucalyptus. Many montane species or ones from Tasmania can grow well in The United Kingdom. Any generalisations I make about Eucalypts are often made from my own experience of a limited number of species.

The fruits of Eucalypts, called gumnuts, are small woody capsules. They vary in size from that of a small pea to that of a large pea. They ripen at least a year after flowering, so flowers and fruits can be found on the same branch. In the photograph they are the small black dots along some of the bare twigs.  Eucalypts give up on leaves and branches that are not photosynthesising well comparatively quickly. If the base is shaded they grow tall and straight with clear trunks. The photograph is of a branch above 20feet of clear stem.

All gumnuts are fairly similar. The capsules being closed by usually 3 or 4 valves which open as the fruit dries.  The shape of the capsules and the valves is a useful indicator of species as many eucalypts are similar and they do hybridise. 

Some different gumnuts. The 2 black spots above the gunnii and the glaucescens are seeds.
The brown speckling around the gunnii is chaff a padding from inside the capsules. 

 The ideal shape for a eucalypt for fuel logs is tall and thin. This means that seed has to be collected from felled trees or branches cut with a pole saw. I try to collect small branches that have full size green gumnuts and place them in large clear plastic bags. The idea being the seeds can still mature if they are not and the will slowly dry out.  

When the valves start to open I strip the gumnuts off the branches and put them into a small plastic bag to finish drying out and releasing their seed.
The bags get shaken so the seeds and chaff, an inert filler, can fall to the bottom. It is then a mater of separating off the gumnuts. The seeds are tiny and are the black specks. Kept dry they can remain viable for years. The bag probably contains a thousand seeds. The seeds are sold by weight and include some chaff, which is very light. 

Planting the cleared area at Pit Wood

 Planting the cleared area at Pit Wood. Winter 2021/22.

The bulk of the 100 Douglas Fir and 100 Pedunculate Oak have been planted. They are planted in rows of species, two or three rows of each species alternately. It will remain to be seen how well each grows and which are allowed to go to maturity. The Douglas fir should soon be taller than the Oaks, with narrow crowns they can be left a bit longer after over topping the Oak. It may be possible to control the rate of growth of the Douglas and keep them longer by pruning lower branches to prevent them interfering with the Oaks growth too early. There is no plan for the established conifers, their fate will  be determined later.

Newly planted trees in tree guards, some repaired and reused.

It is standard practice to grow Oak with a "nurse crop of conifers". The faster straighter growing conifers encourage the Oak to grow tall and straight. They are then removed, usually in rows a process known as line thinning. This allows the oak to expand its crown. If the thinning is left too long the trees that are left may be tall and thin so not able to withstand gales once the wood is opened up. Slower growing conifers are often used as they can be left longer. The hope is always that the value of the thinnings will  cover  the cost of their felling. During the 1980's and 90's in particular this wasn't the case and thinning was not done to the detriment of the crop. The poor state of many commercial woods can be attributed to this.

Douglas Fir is not normally used as a nurse for Oak due to its rapid growth after a few years. I am using it in a small area, hopefully it will be possible to have sufficient good trees of one of the species to form a final crop.

The Aspen and Alder stumps are small enough to be removed at any time in the next few years, when it is thought they are interfering with the growth of the planted trees. They mark the 3 x 1.5m spacing reused for the new planting and any coppice regrowth will raise the humidity through the summer. I have also planted some Eucalyptus E. dalrympleana as a cash crop it will be removed in 5-10 years depending on how all the trees develop. If they need taking out before they are a small log fuel size so be it. They will provide shelter from the wind, raise the humidity, and lower the water table through the winter.