The Bull Creek groves in Humboldt Redwoods State Park run six kilometers east to west, starting at the confluence of Bull Creek and the South Fork Eel River and extending west to a short distance past the Mattole Road Bridge over Bull Creek. All the tall redwoods (those over 100 meters in height) in the Bull Creek groves are within 225 meters of Bull Creek itself. Therefore, the area with very tall redwoods encompasses about 2.7 million square meters / 270 hectares / 670 acres. The tall redwoods are more or less uniformly distributed throughout this area, which is known as the “Bull Creek Flats”.
Despite what a sign says, the Bull Creek Flats have NOT been a wilderness for thousands of years. This area was long used by Native Americans, especially in the winter when salmon were in the creek. In the present day Mattole Road runs through the entirety of the Bull Creek groves, and the area is well trailed, on both the north and south sides of Bull Creek. You can virtually drive Mattole Road through the Bull Creek Flats using Bing Maps (this area is not available on Google Earth Street View).
John D. Rockefeller Jr. donated $2 million in the late 1920’s to purchase the Bull Creek groves and a portion of the surrounding hillsides from the Pacific Lumber Company. That sum was matched by state of California taxpayers to complete the $4 million purchase of approximately 9,400 acres encompassing the Bull Creek Flats, Dyerville Flats, and some of the surrounding hillsides in 1931. This is why the area in the present day is called Rockefeller Forest, though John D. Rockefeller Jr. preferred the name Bull Creek – Dyerville Forest.
Coast Redwoods are the dominant canopy species in Bull Creek groves. The coast redwood is the only living tree species with more than a handful of individual trees over 100 meters in height. There are approximately 2,000 coast redwoods over 100 meters in height. Of these 2,000, about 800 are in the Bull Creek groves. About 25 of the approximately 45 trees in the world over 110 meters in height (all coast redwoods) are in Bull Creek groves.
Notable trees marked on older maps for this area include the Rockefeller Redwood (Tall Tree), Giant Tree, Flat Iron Tree (now fallen), and the Giant Braid.
Lower, Middle and Upper Bull Creek Flats
Although the Bull Creek groves (Bull Creek Flats) are continuous, sometimes the area is subdivided into the lower, middle, and upper Bull Creek Flats. Using 2018 LiDAR data, I have created three derivative maps detailing the crowns in each area color shaded by ten meter height increments, stopping at 100 meters. The crowns with white shading on top are over 100 meters, and there are about 800 such crowns along Bull Creek. The tallest tree in the Bull Creek groves is Stratosphere Giant, which is about 114 meters tall. Its specific location can be found through a standard web search.
A Photo Tour of the Bull Creek Groves
Below are photos I took from 2014 though 2019 of locations in the Bull Creek groves. They give a good overall idea of what can be found on the Bull Creek Flats, and some specific additional facts are included in the photo captions.
I have also created a three minute You Tube / Power Point on the Bull Creek groves. There is some background music, please forgive the middling skill of the piano player (me).
Coast redwood tree height is of great interest, as these are the tallest trees currently growing on our planet. There are about 2,000 trees over 100 meters in height, and all of them (except one or two) are coast redwoods. Then the tallest coast redwood is a little over 116 meters in height.
There are longitudinal studies of redwoods over their range, centering on eleven defined plots, each about 10 m x 1000 m in size, with two each in Jedediah, Prairie Creek, and Redwood National parks and one each in Humboldt Redwoods, Montgomery Woods, Samuel P. Taylor, Big Basin, and Big Creek Parks and Reserves. All the trees and vegetation in the plots are measured every three to five years and results are tracked over time.
The overall consensus is the redwoods in the northern plots are holding their own, and in fact growing faster than ever based on dendrochronology studies. Tan oaks, a companion species to old growth redwoods, are having difficulties due to a spreading root disease (SOD). Then hemlocks have become susceptible to invasive mistletoe spreading up trunks. A couple very tall hemlocks in Jedediah Smith upland have fallen or are standing dead. The largest tree that fell in the plots was a very large Douglas Fir in the Redwood National Park upland plot.
Then there are lists of the tallest redwoods (those over about 105 meters or otherwise locally tall for their area) where these trees are measured every so often, some every year and others perhaps once a decade.
The tree heights for redwoods in the plots and on the tall tree lists are very accurately measured by Laser Range Finders or by crown tape drop (with measuring pole for the tip). Obviously only so many redwood trees can be assessed in this way.
However, there is another way to track canopy height. Not exact height, but pretty close. It is LiDAR.
LiDAR data is available for many of the areas with tall redwoods. Availability and download tools are available on the National Map, NOAA Elevation Data, and Open Topography LiDAR Portal. For certain areas, LiDAR data is available starting from 2007 (though typically private and not available for download) all the way through 2020 (later years are typically public and available for download). Be sure to download all points and to work in meters.
I would be remiss not to lobby for public availability of LiDAR data captured for public lands, especially if the LiDAR acquisition was partially or fully publicly funded.
Using LiDAR Data to Measure Canopy Height Over Time
In order to use LiDAR data longitudinally, it is necessary to create LiDAR derivatives for individual surveys, export the height above ground rasters created from these surveys, then compare the height above ground rasters between surveys done at different dates.
To use LiDAR point cloud data to create height above ground, there are several sources with detailed steps. Let me briefly summarize a method I find works well:
Software – ArcGIS Pro
Filter point cloud to ground points, use Geoprocessing Tool “LAS Dataset to Raster” to create a dem layer. Within Tool use Interpolation type “Binning”, Cell Assignment “Average”, Void Fill Method “Natural Neighbor”, Sampling Value “1”, Z Factor “1”.
Next filter point cloud to first return points, use Geoprocessing Tool “LAS Dataset to Raster” to create a dsm layer. Within Tool use Interpolation type “Binning, Cell Assignment “Maximum”, Void Fill Method “Natural Neighbor”, Sampling Value “1”, Z Factor “1”.
Now that dem and dsm layers have been created, use Geoprocessing Tool “Minus” and subtract the dem layer from the dsm layer. The resultant layer is the tree height. A map can be created to show colors by height band. However, at this point, to access forest height over time, we are interested in exporting this information to a table.
This height layer to table process is a little involved, there is a paper on it, link is here:
Since a raster height layer has already been created, we can skip steps 1 and 2 and start with step 3.
Run Geoprocessing Tool “Raster to Point”. Here the input file is the height above ground layer, the field is “Value”, and an output file will be named and created. Let’s call this result RasterT_FoundersGrove.
Run Geoprocessing Tool “Add Geometry Attributes”. Input features are “RasterT_FoundersGrove”, Geometry Properties are “Point x,y,z and m coordinates”, Length Units are “Meters”, Area Units are “Square Meters”, and Coordinate System is “Current Map”. These attributes are then added to “RasterT_FoundersGrove”.
Run Geoprocessing Tool “Add Surface Information”. Input features are again “RasterT_FoundersGrove”. The input surface is the height above ground layer, for Output Property “Z” is checked (this is height above ground), the Method is forced to “Bilinear” (don’t worry the information behind this Method on point averaging and sampling, it will not be done due to how the height above ground layer was created), and leave Sampling Distance blank. This adds surface information to RasterT_FoundersGrove.
Run Geoprocessing Conversion Tool “Table to Table”. Input Rows are again “RasterT_FoundersGrove”. The output location will default to the project database but can specify any available folder. The Output Name can be anything but the .csv extension must be explicitly included. For this example, we can call it FoundersGrove.csv.
The output CSV file will look like this:
Both grid_code and Z are height above ground in meters. Then POINT_X and POINT_Y are meters east and north in the Universal Transverse Mercator coordinate system.
In a general sense, the 2007 Private LiDAR covers all the northern redwood parks. Then there is 2017 and 2018 public LiDAR for northern redwood parks south of Eureka. There is also updated LiDAR, from about 2016, for redwood parks north of Eureka but for now it is private.
For Founders Grove, there is 2014 and 2018 LiDAR available. I followed the process noted above and used a max function against the final csv files to find the tallest point within each of 430,000 square meters downloaded for both 2014 and 2018. I then did these height comparisons:
For points in same square meter where the height was over 70 meters in both 2014 and 2018:
Crown Sq Meters
Avg Hgt 2014
Avg Hgt 2018
Std Dev of Chg
Median of Chg
Height Changes in Same Square Meter Canopy Location in Founders Grove, Canopy Over 70 Meters
Then for points in same square meter where the height was over 90 meters in both 2014 and 2018:
Crown Sq Meters
Avg Hgt 2014
Avg Hgt 2018
Std Dev of Chg
Median of Chg
Height Changes in Same Square Meter Canopy Location in Founders Grove, Canopy Over 90 Meters
In Founders Grove, the trend is increasing height, of about 0.14 meters per year from 2014 to 2018. The median height change was an increase of 5.5 inches per year, with 70% of crowns gaining height.
From this information Founders Grove growth can be assessed as increasing in height, and this is a favorable condition in relation to forest health.
This same comparison can be done over longer periods for many redwood park areas as LiDAR data exists in both the 2007-2010 time frame as well as the 2016-2020 time frame.
As Inspired by Beethoven’s Seventh Symphony, Second Movement (Allegretto), “Knowing”, most watched You Tube version here:
For more photos and associated music in You Tube, please go here
Movement 1 – il fiurne icontra l’oceano (River Meets Ocean)
Redwood Creek flows into the Pacific Ocean just south of Orick, California. The outflow area includes some rocky headlands, pastures, and a large earthen levy. The levy is to mitigate the effect of offshore earthquake induced tidal waves. Not too long ago, and for thousands of years before that, native peoples used this area in the winter for fishing and hunting, with their villages located a few miles upstream in sunnier and warmer areas near Emerald Creek (a feeder creek to Redwood Creek). The native peoples also used the Bald Hills area in the summer and fall for hunting and collecting acorns. The Emerald Ridge, Dolason, and Tall Trees trails are likely routes originally used by the native peoples to travel between the Bald Hills and Redwood Creek.
One way to access this area is a pleasant beach walk from the Kuchel Visitor center. It is a lot safer and warmer to walk near the high tide line versus in the surf, as the water is cold and sneaker waves can knock a person down and drag them out into the ocean.
This is an area where the steady outflow of Redwood Creek can be expressed by soft string music, then the waves are represented by the thump of the kettle drum, and the sadness of what was lost through minor scales played by oboes and clarinets, particularly the first wailing call at the start of the movement.
This movement covers Redwood Creek from the ocean to the turn southward, and the first one minute forty five seconds of Beethoven’s allegretto.
Movement 2 – inizia la grande foresta (The Great Forest Starts)
Moving upstream Redwood Creek turns south, winding around the base of Orick Hill. It is in this area the great Redwood Creek forest starts. Here the trees are not quite as tall as further upstream, as sunlight is suppressed by coastal fog for much of the year. Yet the tallest trees in this area approach 330 feet in height. There are open fields on the east side of the creek, through fire maintenance by native peoples and now the National Park Service. Elk are in this area, and there is still a hint of the Pacific Ocean as evidenced by large Sitka spruce trees in places near the creek. Big mossy maples are also around, giving a hint to past flooding events.
This area is a transition zone between the maritime area and the tallest trees which are further upstream.
In this movement there is a building, repeated melody played in the string section. It is a hint of what is to come, as the tall trees are all round and become more numerous moving upstream. This would cover about 1:45 to 2:45 in Beethoven’s piece.
Movement 3 – la foresta che tocca il cielo (The Forest That Touches the Sky)
Starting immediately around the area of the north seasonal foot bridge, the tree height skyrockets. Here is the start of a six mile sweet spot, with nightly fog providing year round moisture for leaves through absorption and for roots through fog drip. But then the fog retreats during the day and allows the sunshine to provide energy for photosynthesis. There are many side streams with gulches and gullies, where the tall trees can find wind protection. The hillsides give a push to the water column of each tree, as water first flows downhill a few feet from the uphill side of the trunk to give a boost to the osmotic pressure that brings that water up through the xylem to the crown. There are also flats near Redwood Creek with very rich soil. The tall redwoods grow all over, on the hills above Redwood Creek, up the side streams, and on the flats. Only the trees on the flats can be accessed safely, Tall Trees Grove year round, then the other flats only when Redwood Creek is running low. It is exceedingly dangerous hiking off trail along the hillsides and creeks above Redwood Creek and its side streams.
In this area there are perhaps 35 trees above 350 feet in height. Before the area timber harvest started in 1950 there were probably four times as many (about 140). How tall was the tallest, was it taller than 380 feet? We’ll never know for sure, and it is very special there are a couple trees around 380 feet in height, still. There is an excellent article on historic tall Douglas firs and Coast redwoods by Micah Ewers, it is here:
In this movement the full orchestra pitches in on the main melody, playing loudly, with the beat kept by a thumping kettle drum. Each beat of the drum represents a 350 foot tree, and each note in the melody signifies the magnificence of the forest. There are also some intervening sections with soft undertones by the woodwinds that signify what was economically gained and then lost as the timber was harvested from 1950 to 1977.
This movement covers about 2:45 to 7:05 in Beethoven’s opus.
Movement 4 – magnificenza sopra il torrente (Magnificence Above the Stream)
Starting around the Emerald Creek inflow, Redwood Creek becomes more stream like and a lot of the forest above the creek is second growth. But old growth remains, with a few trees here and there trying to touch 350 feet. The nightly fog inflow starts to dissipate in this area, and the forest becomes drier, especially in the summer. This is a hard to reach area with some scenic spots, I have been told.
This movement is carried by woodwinds and the strings are plucked at times, representing resignation that the forest is dwindling and losing height. But every now and then the orchestra chimes in with a new short bright melody, like a scenic early evening sky, representing the occasional towering trees that occur in this area. It is still very good. Then at the very end the main melody returns, for a few short notes. This represents the end of the old growth.
In Beethoven’s opus this runs from about 7:05 through to the end at 9:10.