Groves of Tall Redwoods – Changes over Decades, Centuries, and Millennia

1       Tall Redwood Groves – Recent Changes in Height

Redwood tree height measurement came into its own in the 1990’s.  Skilled researchers and naturalists combined laser rangefinder technology, LiDAR height estimation, hiking and climbing skill, and direct tape drop from the canopy to create a nearly complete inventory of tall redwood trees throughout their range (with the exceptions of Six Rivers National Forest and Headwaters Reserve, which have not been thoroughly assessed). From this it was determined redwoods over 100 meters (328 feet) in height were uncommon, totaling about 2,000 trees.  And redwoods over 350 feet (106.7 meters) in height were very uncommon, totaling about 230 trees.  Each tall tree is remeasured every five years or so, with the tallest trees having more frequent measurements.

 I don’t have direct access to the 15-25 years of longitudinal height data for tall redwoods but through research I was able to find height information for the tallest known trees in the year 2000 as well as their remeasured heights as of 2015.  There were 129 trees over 350 feet on the 2000 list, indicating many more 350-foot redwoods were yet to be identified, particularly in Redwood National Park.  Here are the height changes for these 129 trees in inches growth per year (parks with smaller tree counts are excluded) on the left axis and 2015 height on the right axis (line).

On the chart the trees are grouped by Bull Creek (Humboldt Redwoods along Bull Creek), Eel River (Humboldt Redwoods along Eel River including Rockefeller Loop), Montgomery (Montgomery Woods State Natural Reserve) and Redwood (Redwood National Park).

Height Change (left axis and bars) and 2015 Height (right axis and line)

It is evident in all four areas most trees had height increases over fifteen years.  Nine trees lost height, a few in each area.  Median height growth was about three inches per year.  Over the past few years two of the trees in the data have fallen.

The chart also includes tree height in 2015.  Correlation between 2015 height and height change is 0.53, correlation between 2000 height and height change is 0.02.  So height change was not related to initial starting height.

Here is summary data related to the chart.

Height Changes Summary

This data indicates the canopy of very tall redwood trees increased three feet from 2000 to 2015.   The canopy in 2000 was the result of several thousand years of forest development. Then why did the tallest existing redwood trees increase on average another three feet in height from 2000 to 2015?  Some potential contributing factors:

  • More sun reaching the leaves of edge habitat trees due to cutting of nearby trees from 1860-1979.
  • Fire suppression
  • Increased atmospheric CO2 providing more energy for photosynthesis

2       The Future of These Tall Trees

Based on plot information, 350-foot tall redwoods are between 700 and 2000 years old, with the median age 1180 years.  It is very likely almost all of the current 350-foot tall redwoods will fall over the next 1000 years, being replaced by grow in from trees currently under 350 feet and trees yet to sprout.

Let’s test this against the known 350-foot trees to fall in the last 30 years in Humboldt Redwoods State Park.

Humboldt Redwoods Fallen Trees

It can be expected about ten percent of the tallest redwoods will fall every 100 years, with 3-4 trees falling each decade.

Before falling many trees will lose and regain height over time.  About two thirds of the 350-foot redwoods in study plots have reiterated tops.

3       What is the Maximum Height for Redwoods

The current tallest tree is about 381 feet tall.  There are four trees around 375 feet tall or taller, and all four are gaining height.  Then the data shows the canopy for very tall trees in general is increasing by about one foot every five years.

So will there be 385-foot redwoods in 20 years?  Could be.

Will there be 390-foot redwoods in 50 years, and 400-foot redwoods in 100 years?  Maybe.  The theoretical maximum height based on tree structure and physics has been calculated to be 425 feet.  There is no reliable historic record for a redwood tree over 400 feet in height.  One was measured right at 400 feet about fifty years ago along Wilson Creek by an expert timber cruiser.

Will some second growth Douglas Fir beat all the redwoods and get to 400 feet first?  Maybe, but then again the reliable historic maximum height for Douglas Fir is 393 feet.

Thanks for reading.

4 thoughts on “Groves of Tall Redwoods – Changes over Decades, Centuries, and Millennia”

  1. Hey Mark, Great post! It’s really exciting to wonder what our future giant trees will look like in 25, 50, or 100 years. Maybe they will really take off with increasing c02!… 😉 but, I’m betting on one or more four hundred footers within 25 years, either within the redwoods or extant Doug fir forests. Maybe one exists now.

    It’s amazing how much knowledge has been expanded, and has been learned in the past 20 years with LiDAR survey, and expert big tree enthusiasts/discoverers such. The ceiling has been pushed 20-30 feet (or more), up from what we thought they could attain in the 1940-50s. And now so many trees have been discovered over 350 feet, (the old upper limit), I really do believe ‘some’ of the old stories of past impossibly tall historic behemoths will be / are being vindicated. The 425 feet threshold from that 2004 study by Koch et al, I think, shows at least a considerably higher potential than some had previously envisioned, even just, say, 20 years ago.

    Yet ironically, I think trees in these tall ranges were being felled all along!:

    400 feet at Wilscon Creek, c.1960s-70 is intriguing! Thanks for that report. I gotta look that one up, as it joins the ranks of my historic dream team.

    I found a news/ timber bulletin report yesterday, of a 427 ft redwood, 77 ft circumference, 274 ft to where it fractured (still 9 ft diam at the break) when it hit – from Eel River, felled February 14th, 1893, 2 miles from Engelwood, – the report of the fall could be heard for “ten miles”, so it is said. It was apparently bucked and measured by J.H. French, the father of Enoch “Percy” French, first ranger of the Northern California Parks / Redwood state park. The press quoted J.H. French that he thought the tree was 417 feet as it stood. Photos of the butt log exist online, before it was sent to the Chicago Expo, and Pan American Expo. The Niagara Museum now has the 24 foot wide tree bark house/exo-skeleton. A rather intriguing exhibit!

    A few miles north, we have a story from 1886 of a 424 foot tree that made 21 cuts, from south Fork Elk River. It briefly was reported in several papers and bulletins. No names of cutters recorded, other than Elk River Lumber co. So it remains a less reliable report, though still in the proximity of other tall trees, of the Eel/Elk river valley systems.

    There are a few other cruiser reports or second hand stories of trees estimated at over 400 feet at Eel river, and Russian River in the 1880s-1890s. One tree at Eel river was said to be 401 feet tall, and 24 ft diameter 8 feet off the ground, (presumably felled ) as reported by A. Roman in his 1882 book.

    We have a story of a 390 ft + butt, felled at Redwood Creek by Arcata Lumber Co. 1960s, according to Martin Litton, of Sierra Club in 1980s.
    A few trees estimated at 380-390 ft in Humboldt co., reported in 1927 by Ralph Townsend of Save the Redwoods league. These may have been early cruiser reports he was getting.

    380 ft – A tree felled by B.F. Porter on his timber tract in Eureka, California in 1914 hit the press, and timber bulletins. The monster was said to be 26 ft diameter, and 260 to first branch.

    The 1905 story of the Lindsey creek tree, 390+ ft, and 30 ft diameter, on the ground, and still 9.5 feet thick 260 feet up, is most curious.

    And there are apparently some old stories of trees over 400 feet felled around Arcata and Orick Flats in the 1850s. There are probably many more historic reports.

    1. Hello Micah

      Wow, thanks much for sharing the information on tall redwoods in the past. I think finding Hyperion for sure validates the stories about the 380- 390 foot redwoods along Redwood Creek and its tributaries.

      For Elk River and Eel River, the reports as you describe are amazing and the heights are not impossible. There may have been a sweet spot with really tall trees that was totally cut over.

      The Douglas Fir grows a lot faster then redwoods and has past records of trees at 400 feet. I see where there is a second growth Doug fir just under 300 feet, maybe in 20 years second growth Doug Fir height will be higher than the current tallest old growth Doug Fir which is about 328 feet. Then over time maybe these will approach 400 feet.

      Mark

    1. Hi Richard

      Checked the site redwoodcoastparks.com, and like it a lot. Nice trail selection and photography, and good review of the beaches, which are often overlooked. I didn’t realize there were so many cabin and house rentals in the area, nice array to choose from.

      Mark

Leave a Reply

Your email address will not be published. Required fields are marked *