Scotlands national tree, the Scots Pine [Pinus sylvestris] has been present in Scotland since the post glacial period, about 9000 years ago [1,2] It is often called the Caledonian Pine and was given this name by the Roman Emperor Ptolemy in about 200 A.D. Although the original pine forest has been gradually reduced largely due to felling and over grazing there are still remnants of the ancient forest scattered throughout Scotland and there is evidence that these surviving pines are lineal descendants of the early post glacial trees. [2]
There has been considerable efforts to re establish the Caledonian Pine trees in Scotland by fencing to allow natural regeneration [Figure 1] and by planting from seeds taken from the surviving trees.
Figure 1. Natural Regeneration of Pine Trees after fencing.
This website describes a method for growing Caledonian Pine trees from seed. The method described is by an enthusiastic amateur with no background in silviculture
Cones are collected between April and May from trees in one of the remnants of the ancient Caledonian Pine Forest in Glen Lyon. The cones turn from green to brown as the seeds ripen so this will indicate which cones to collect. The cones may be reluctant to open and in these cases they may be put in a container and stored in a warm cupboard. It may take several weeks before the cones open and discharge their seeds [3] Figure 2 shows closed cones, figure 3 shows open cones and figure 4 shows seeds ready for sowing.
Figure 2. Closed cones.
Figure 3. Open cones.
Figure 4. Seeds for sowing.
The seeds are planted in seed trays using 50/50 mixture of potting compost and horticultural sand or horticultural grit. The trays are placed in a non heated greenhouse. The seeds should be planted at a depth approximately twice the diameter of the seed. The seeds usually germinate in 3 to 4 weeks [figure 5] If a green house is not available the seeds may be planted out in a seed bed but will need to be protected to prevent them from being eaten by birds etc.
Figure 5. Seedlings at approximately 6 weeks.
Once there is new growth in the seedling it can be transplanted into a 6ins pot. The new growth should be well established before potting out. Figure 6, figure 7.
Figure 6. Early new growth in the centre of the seedling not ready for potting out.
Figure 7. Well established new growth now ready for potting out .
Figure 8. When potting the seedling hold it by the needles to avoid damage to the roots.
Once the seedling has settled in the pot for four or five days it should be put outside to harden off. The trees are repotted into a larger pot when the roots fill the bottom of the pot. The trees can be planted out when they are 4 - 5 years old depending on the growth.
Figure 9. Tree at 2 years.
Figure 10. Tree at 3 years.
Figure 11. Tree at 4 years.
The above photographs were taken in the green house for convenience. Once the seeding has been put outside it should remain there permanently.
Many of the Caledonian pine trees grow on a peat based soil but they thrive on most soils and can be planted almost anywhere, provided they are protected from browsing animals, particularly red deer. However trees planted in exposed coastline areas will have a higher than normal mortality due to a combination of wind and salt air and those that survive maybe somewhat stunted.
It is a most rewarding experience to take a tiny pine seed, propagate it into a pine tree, plant it out at 4 - 5 years and know that it will reach a height of about 200 feet, will grow for 250 - 300 years, and will contribute to the preservation of Scotland’s ancient Caledonian pine trees. The trees will absorb carbon dioxide and potentially harmful gases such as sulphur dioxide and carbon monoxide from the air and release oxygen which will help to offset the build up of co2 in the atmosphere and reduce the “greenhouse effect”
Bibliography
1 Bain, C. 2014 The Ancient Pine Woods of Scotland 2 Steven H. M. and Carlisle, A., 1959 The Native Pine Woods of Scotland 3 Togood, Alan. 1960 Propagation