No hurricanes on the west coast.

stable weather

weather moderated by the ocean

lower population density. both of native americans and europeans until late last century.

lifted from arborday:
The Eastern White Pine tree has been referred to as "the monarch of the forest." Some that greeted the first settlers reached a height of 250 feet with diameters of 6 feet. They were a bonanza for England in colonial times, as they met a vital military and commercial need for sailing ship masts. Since the colonists were rapidly using up the existing supply of trees close to the ocean that were large enough for masts, the Royal Navy appealed to Parliament. As a result, in 1691 Great Britain imposed the first of the so-called "broad arrow" acts, so named because of the axe mark placed on the reserved trees by the king's men, that reserved these trees for the English government. Growing resentment to the crown's appropriation of the choicest White Pines helped precipitate the Revolutionary War, and the first flag of the revolutionary forces even had a White Pine as its emblem.

And from that other bastion of reliabilish information wikipedia:
One survivor is a specimen known as the "Boogerman Pine" in the Cataloochee Valley, Great Smoky Mountains National Park. At 57.55 m (188.8 ft) tall, it is the tallest accurately measured tree in North America east of the Rocky Mountains. It has been climbed and measured by tape drop by the ENTS. Before it lost its top in Hurricane Opal in October 1995, the Boogerman Pine was 63 m (207 ft) tall as determined by Will Blozan and Robert Leverett using ground-based measurement method

so yeah, maybe there were 250 foot pines growing in the east coast before the mid 19th century, what they need to do is conduct a study of how tall they could theoretically grow under optimal circumstances, like the study they have done for redwoods and firs.

There are Ponderosa pines in oregon that have reached about 269 ft, Michael Taylor the big tree researcher who found Hyperion, thinks the biggest ponderosas logged in the area may have reached 300 ft at the best sites.

who knows. Our few remaining big trees are still growing, and new champions are found every year in the forests of oregon, wa, and california by a select number of committed enthusiasts who probably number in the tens.

The redwoods once grew all over the world millions of years ago, and who knows how tall they may have grown under different environments and conditions. Lower altitudes generally afford a longer growing season for conifers, for example, The Washington Forest Reserve by Horace Beemer Ayres, Geological Survey (U.S.) 1899. on pg 295 mentions a Douglas fir which grew at the alluvial bottom of the Skagit river and measured at 315 ft length after it was cut by lumbermen, and where it was cut at 7 ft above ground, the stump recorded 253 annual rings. Ayers collected his data on the spot from dozens of trees felled by lumbermen.

AT the same note fir trees east of the cascades can reach 250 years and grow no higher than 80 or 90 feet. Altitude is a big factor in the forests of the Pacific forests, most of the super tall historical trees, verified and unverified grew in the sub 1,500 feet elevation -- and primarily only a few hundred feet above sea level. So I think Britain could potentially be the spot for some real big trees -- but I doubt it will, because with 60 million people on an island, with only a few forests, it will never contain the vast space needed for giant timber forests the likes of which were present in Oregon and Washington pre-1900.

Many of the fir and redwood forests in the pacific northwest are free of branches for 100-200 ft. It's the sheer height of the trees of the west that are striking. Even for people who were born and raised in the northwest, such as myself, there are still areas where I'm surprised at how tall the trees are. And fir trees appear even taller than they are because of their slender trunks.

Vicinity of Coos Bay is considered the prime habitat for Douglas fir. There has been much logging there.

Jimmy - I don't think that any foresters or forest scientists honestly believe that there is more old growth today then there was 100 years ago. It is impossible, because a 100 yr old forest is still considered "second growth", and can not compare -ecologically or in tree mass - with a true "old growth" forest.

Just sayin'.

According to Dr. Bob Zybach of Oregon the old growth in the Northwest was comparable to today's old growth over a century ago in the settlement era. He studied fire history in the state of Oregon and believes most of the trees were second growth when the white man came. Zybach has said reports of Douglas fir in excess of 300 feet are mostly stories that cannot be documented, and he has said that the city of Vancouver BC was a prairie before the white man came. I think his views are the minority opinion. He was a reforestation contractor for 20 years, so I value his input.

Most estimates I have seen suggest between 70 and 90% of the biggest and oldest Douglas fir forests have been logged in the past 130 years. In some places like Southern Vancouver Island up to 99% of old growth fir is said to be gone. One need only look at the hundreds of old logging photos of giant fir and cedar to get an idea of how large the lowland forests once grew, and in places like present day Seattle, and Vancouver BC. To deny all of this pretty much tells me one would have to be a lobbyist for the timber industry, but that is just my gut feeling.

New Zealand, southern Australia and Tasmania have some really tall trees in the temperate and rainy valleys. Some of these forests contain hardwood trees that are as tall as the fir trees of the west. The Eucalyptus Regnans may have been the tallest tree species in the world 150 years ago. Dozens of trees were measured by surveyors after they were felled and reported second hand to Baron Von Mueller of Melbourne's botanical garden in the 1860's to 1880's. The tallest were said to be over 400 foot. The biggest Eucalyptus documented first hand was reported to the assistant commissioner of lands on Feb. 21, 1872 by the state inspector of forests, Mr. William Ferguson. His tape line showed one fallen specimen to be 435 ft long from the base to a broken top 3 ft thick -- suggesting the tree may have been taller still. Ferguson reported other fallen trees which exceeded 350 ft long in the watts river and its lowland tributaries.

The tallest known tree in all of Australia and Tasmania today barely reaches 328 feet.

Douglas fir sets winter buds in summer or fall and then does not grow again until these open in spring.