Native Pinewoods of Scotland

I was conducting some research into native pinewoods in Scotland and this post is a summary of the information on native pinewoods.  The distribution of native Scots pinewoods is illustrated on the Joint Nature Conservation Committee website, elsewhere the Forestry Commission maintain a Native Pinewood Inventory of sites.

Distribution of Caledonian Forest
http://jncc.defra.gov.uk/publications/JNCC312/habitat_comparison.asp?FeatureIntCode=H91C0 

The conservation numbers are as follows

• 84 locations are currently attributed as sites of native pinewoods.
• 10 of the most notable areas with native pinewoods have been designated as Special Areas of Conservation (SAC), 
• The remainder mostly designated as Sites of Special Scientific Interest (SSSI)
• An inventory of Caledonian Pinewoods has been drawn up by the Forestry Commission and the inventory contains all the known pinewoods with more than 30 individual trees where the balance of probability is that they are genuinely native (semi-natural), that is, descended from one generation to another by natural seeding.
• In 1998 the inventory stated that there was a Pinewood (core) area 17,882 ha, Regeneration zone 25,399 ha and Buffer zone 92032 ha.
• For a Pinewood to be accepted as a registered source of native scots pine seed it needs to be isolated from pine of non-local origins, normally at least 400 m.

Ballochbuie Forest SAC, 2014

Information that relates to the native pinewoods of Scotland

Early observations

• Stephens and Carlisle record in their 1959 publication Native Woods Pinewoods of Scotland that there was some controversy and speculation about the quality of native Scots Pine in the 18th C. Timber merchants and tree growers were adamant that there were two distinct species of Scots Pines producing vastly different timber quality. Others disputed that there wasn't two species and instead observed that climate and site determined the quality. Another point of view was that the Scots Pine needed time to mature before being assessed for timber quality and that 30 year plantations were not a reliable guide to mature tree timber quality. Another view was that some planting had been undertaken with 'superior' continental pine seeds, mixed in native seeds. And someone else pointed out that native Scots Pines in the highlands, do not grown in regimented plantations, but in exposed locations upon ground unfit for anything else and when mature demonstrably produce high quality timber.
• With the issue of timber quality highlighted, there then ensued a concentrated effort starting in the late 18th C to  determine every conceivable physical characteristic of Scotland's Scots Pines; morphology, cone size and shape, seed weight, seed colour, bark character, needle length ...
• Scots Pines were also characterised from Switzerland, Sweden, Finland, France, Germany and Scotland. Numerous species/varieties of Pinus Sylvestris were proposed/named based on morphology, habit, bark or combinations thereof.
• Bark studies showed distinct varieties on trees with numerous designations of ridge, mussel, flake, plate and intermediaries. Someone inconveniently pointed out that the character of bark also changes over the course of a tree's lifespan ... Nonetheless, in Scotland's native pinewoods there appeared to be a regional flavour of bark characters.
• 18th and 19th Century plantings of known continental provenanced Scots pines in Scotland proved disappointing. The ferocity of a 'heelan hooley' was too much for some plantations and the combination of exposure to rain/wind/hail/freeze thaw conditions, affliction from disease/pests produced inferior sub optimal growth in continental trees.

Plate and flake bark, Glen Affric ~ 2013

• Forestry Commission provenance trials 1929 - 1942 indicated that Scots Pine from continental Europe were superior to Scottish provenanced Scots Pines in southern England and were inferior in Scottish trial locations. Southern England has more of a continental climate, Scotland has an oceanic climate. There was no record on the soil/bedrock geology of the trial sites.
• When researchers and conservationist arrived at the new Nature Conservancy Council purchased Beinn Eighe National Nature Reserve (NNR) during the 1950's they commented on the differences between the west coast pines and the Highland/Cairngorms pines.
• Limited trials at an exposed site Glen Trool in 1965 determined that Scots Pines from Loch Maree coped better with Winter Blast than other trees.

Coulin native pinewood, Glen Torridon ~ 2012

Genetic diversity and consequences

• In the late 20th and early 21st Century genetic research has indicated that the Native Scots Pines are genetically diverse from the European Scots Pine populations and there is also a regional genetic diversity amongst the native pinewoods of Scotland.
• The genetic diversity continues down at the local level in Wester Ross, with the West Coulin pines being distinct from the East Coulin pines and Loch Maree pines, despite being less than 2 and 4 miles away respectively. 
• Beinn Eighe National Nature Reserve (NNR) started a tree nursery in the 1953 from seed collected in the reserve, to grow seedlings that would regenerate the native pinewoods on the reserve.
• In the 1970 the Beinn Eighe NNR closed its tree nursery and the Forestry Commission supplied the Beinn Eighe National Nature Reserve with seed instead from its Black Isle nursery.
• A shortage of seedlings from the nursery meant the Forestry Commission supplied Glen Affric originated Scots Pine seedlings to the Beinn Ejghe NNR, which were planted.
• When the genetic studies of the native pinewoods were made available, the Beinn Eighe NNR had to remove Glen Affric sourced Scots Pines to preserve the genetic diversity of the Coulin Pinewoods and also remove Glen Affric sourced Scots Pines plantations adjacent to Coille na Glas Leitire to preserve the genetic diversity of Loch Maree pines.
• In 1987 Beinn Eighe NNR restarted a tree nursery growing its own local origin seedlings. 

Glen Affric ~ 2013

Dates and pinewood dynamics

• The oldest living native Scots pine trees date from the 1450's AD in Glen Loyne and Glen Derry.
• Palynologists declared Scots Pine colonised Scotland around 8,000 years before present from the north west and slowly spread south.
• Sub fossil Scots Pine retrieved from lochs in the Cairngorms have been dated to just before 8,000 years before present.
• Dendrochronologists are cautiously optimistic of eventually establishing a sequence of 8,000 years of tree ring chronology data for the Highlands of Scotland from subfossil pine material retrieved from lochs and peat.
• The East end of Glen Affric has seen a continuous presence of Scots Pine woodland for the last 8,000 years, whilst the West end of Glen Affric has an entirely different history of Scots Pine woodland with very little Scots Pine woodland for the last 4,000 years. Ecologists speculate that the difference is due to a shifting ecotone due to the steep climatic gradient down the glen or blanket peat and hydrology or a combination of both.
• Historical research has identified a small number of Pinewoods that are recorded in the 17th and 18th Centuries but have either disappeared or are are no longer considered as viable woodland. Some of those pinewoods were already in decline at the time of recording.
• There is a general consensus that the decline of native pinewoods are a combination of mismanagement and climate.
• Palynology studies have been suspect in identifying the physical presence of Scots Pines at sites.
• Climate change is believed to have influenced the ability of Scots Pine to colonise and regenerate on blanket peat.

Screenshot from Forestry Commission