Woodlands For Wales.

[Yorick]

"In southern Wales at least Ash will be a major pioneer and it will need to be managed if it is not to dominate the smaller and/or slower growing species."

The Jungles are posative proof that if things were not managed, the right things would grow. Nature is the only true manager, humans think they know best, and are fighting nature in their attempt to prove they know best. If humans all left the earth tomorrow, the world would clean up and look beautiful all by it's self. It is a true miraculous and wonderful thing.

Some trees/plants do grow quickly, but they also die quicker. I think this is what is so wonderful about nature, it's diversity. These quicker growing and dieing plants give the slower ones things they need to survive. Nature needs everything, humans want to segregate, they like to choose what will survive and what they want to eradicate.

Gradually humans will eradicate themselves completely.

[Cotham Marble]

Originally Posted by Yorick

The Jungles are posative proof that if things were not managed, the right things would grow. Nature is the only true manager, humans think they know best, and are fighting nature in their attempt to prove they know best. If humans all left the earth tomorrow, the world would clean up and look beautiful all by it's self. It is a true miraculous and wonderful thing.

Sounds more like a religious belief, and whatever its merits, it is not going to inform any broader discussion about how woodlands in Wales are actually managed.

Originally Posted by Yorick

Some trees/plants do grow quickly, but they also die quicker. I think this is what is so wonderful about nature, it's diversity. These quicker growing and dieing plants give the slower ones things they need to survive.

That's hardly a scientific assessment of the woodland ecology of Wales (or anywhere else). Across multiple climates/environemtns there is indeed great diversity, that doesn't mean that at various developmental stages low diversity doesn't exist in specific areas. The choice facing woodland managers is how best to facilitate accelerated diversity where the opportunity exists.

Originally Posted by Yorick

Gradually humans will eradicate themselves completely.

Seems as though you don't like humans much, a position which surely makes it problematic for reasoned interaction with others of your species ? Of course I understand that other humans also hold similar views, but it does seem very like medieval dualism except that 'Nature is substituted for 'Spirit' and 'Human' is substituted for 'Corrupted and Corrupting Flesh'. Personally I see humans as intrinsicly part of nature and our terraforming behaviour merely an evolutionary response. That behaviour may well be the source of our own decline, other species have similarly succumed, although they were not equiped with brains that provided foreknowledge of the effects of their own actions. My belief is that we should work with what we've got and manage where we can manage and leave alone that which we we can't - which is a position that at least has the merits of having some possibility of being accepted by a number of my fellow humans.

CM

[Dorts]

Nature, left to its own, certainly does not necessarily produce diversity in all areas.

In Souther England on the chalk, the unimproved grassland is one of the most diverse habitats in the world. It was created by mans efforts to tame the land for his own ends, (now alas a rare and diminishing habitat.

If these chalk downlands were just left to nature, with no management of any kind, they would inexorably, over several hundreds of years, move towards a monoculture of Yew as can bee seen at Kingly Vale in West Sussex. Such a woodland would blanket the ground, crowding out all in its path for possibly 5,000 years or more.
However, chalk grassland on an exposed clifftop position would remain intact, probably the only place that this unique habitat existed in the days of the 'wild-wood'.

A similar situation would occur in Wales wherever man's management ceased.
Some ares would develope into dense woodland with a low diversity of fauna and flora, others the opposite. In the long term each habitat would be ever changing dependent on geology, position, and most importantly; climate!

But it would be wrong to suggest that at any time a particular habitat could not be 'improved' by mans intervention.
Dorts.

[Eryri]

Originally Posted by Cotham Marble

This sequence has no relationship whatever to the two studies quoted. The first of which gives plant cover as dating from 12,000 BP (10,000 BCE), while the second study doesn't even go back past 9,000 BP.

They overlap, and why I presented the known phases from 9999BP.

Originally Posted by Cotham Marble

The Field Studies article gives Birch as the most important tree species at 10,000 BP with Oak and Pine displacing it from 8,500 BP, and then goes on to say "Apart from a few perturbations involving shifts in species dominance and changes in altitudinal limits of certain species, it is essentially this woodland phase that has persisted right through to the present day."

Altitudinal limits is a posh word for 'tree line' and is a very accurate measure of prevailing annual temperature at altitude. The change from birch to oak is significant because birch can survive ling cold winters much better than oak. This can be seen as a present day birch/oak latitudinal boundary in Poland and Russia.

Originally Posted by Cotham Marble

And this is a study of Snowdonia where glacial conditions will have continued far longer than virtually all of the rest of Wales.

No. The end of the younger dryas glacial period was very abrupt. This is evidenced by scree deposition. Unlike previous glaciations, the younger dryas was not influenced by pack ice in the Irish sea. The dormant polygon permafrost features on the Black mountains in South Wales are dated the same as that in North Wales at the same altitude. Existence of later permafrost activity in Snowdonia (even active to present day) is as a result of higher altitude. Please do not confuse differences in altitude in an attempt to deny natural phases of climate cooling and warming.

Originally Posted by Cotham Marble

The RCAHMW article provides a complex aboro-history, but one which may not be braodly extrapalatable outside the study area, and certainly is unlikely to have direct implications for southern Wales. There are other numerous 'confusions' in Eryri's sequence, among them the notion of a Norman heather explosion - the first thing to note is that the position of calluna in the study area is described as: The degradation of the upland soils, primarily from human activity but further exacerbated by changes in the climate, is apparent in this zone by the continuous, albeit low, presence of Calluna (heather). Such low-levels of Calluna are not typical of many other upland areas in Wales at this time, where heather-dominated moorland was common. In the Berwyn Mountains to the southwest of the Clwydians, the expansion of a grass heath progressively dominated by Calluna was dated to c.2900-2500BP (Bostock 1980). Similar Calluna-dominated landscapes are also noted from the Bronze Age at Cefn Ffordd (Chambers 1982), Gors Maen Llwyd, Brenig (Hibbert 1993), and Cefn Gwernffrwd (Chambers 1982), and from the Iron Age at Cefn Mawr, Hiraethog (Lascelles 1995). So any subsequent change in Calluna presence is a local phenomenon. Even then the refrence to 'explosion' concerns a date commencing as early as 1320 BP (690 CE/AD) nearly four centuries before the Normanisation of Wales.

It is not possible to determine whether the 'heather explosions' of Bronze and Iron Age sites are man made or climate driven, as there is no corroborative written record of aggricultural practice. The 'normanisation period' as an expolsion of heather does. It's a change from subsistance 'strip' cultivation to a large scale landholding cultivation.It is significant, and the stratification of pollen in peat bogs record this earlier in England than in Wales. This is not due to a micro climate difference between England and Wales, it is due to changes in the pattern of land ownership and agriculture.

Originally Posted by Cotham Marble

This kind of confused presentation (if not gross misrepresentation) of the chronology of environmental change serves only to obfuscate any useful information about what approaches should be made in current land management.

It's often an accusation by 'natural climate change deniers' to call any data indicating historical natural climate change as misrepresentation, or 'only local'.
Nothing new.

[Eryri]

Originally Posted by Cotham Marble

Personally I see humans as intrinsicly part of nature and our terraforming behaviour merely an evolutionary response. That behaviour may well be the source of our own decline, other species have similarly succumed, although they were not equiped with brains that provided foreknowledge of the effects of their own actions.

How do you know if other species do not have that ability ? The obvious example of a species deliberately and consciously manipulating food stocks for the changing seasons, is the squirrel who hides the nuts, and birds who migrate.

Humans are not the only natural species that engage in terraforming behaviour. Migrating large ruminants in America (mainly bison) effectively maintained huge area of grassland which would otherwise have been naturally forested after glaciations. Similar pressure is placed on the latitudinal boundary of forest by reindeer. The big question to further the discussion....What made the wholly mammoth /giant elk extinct ?

(a) Climate change.
(b) Man.
(c) Themselves.
(d) Competition from other species.

[Dorts]

Originally Posted by Eryri

What made the wholly mammoth /giant elk extinct ?
(a) Climate change.
(b) Man.
(c) Themselves.
(d) Competition from other species.

Most likely answer. (a) (b) (c) & (d). A combination of.
Dorts.

[Spectrum]

Thank you Eryri for your information about tree species over the past 10,000 years. I am just in the middle of reading Britain BC by Francis Pryor and I am amazed to find out how well preserved some of the timbers can be in soils such as peat. Dendrochronology can very accurately date the timber. Have also re-read Oliver Rackham's informative books. Both help us to build a picture of how the trees of Britain have developed!

[Eryri]

Dendrochronology an important tool in "wiggle matching" against the C14 measure. There is still some debate as to the global effects of climate changing events. As can be seen in the Santorini date debate. Francis Pryor is an excellent read. There is an important point about the bronze age, to rear sheep and smelt copper/tin you have to cut down trees.