Tag Archives: humboldt redwoods state park

End of Summer Redwoods Trip

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A couple months ago (mid September 2023) I took a few days to visit the redwood parks and forests in Santa Cruz, Mendocino, and Humboldt counties in California.  I also caught up with a few redwood colleagues, it was nice visiting and doing some walking and hiking. 

Day One – Big Hendy and Little Hendy Groves in Hendy Redwoods State Park near Philo

Big Hendy redwood grove has well maintained relatively flat trails that wind throughout the old growth area.  There are tall trees here, with twenty or so from 330-350 feet in height.   There is also a nice prairie area adjacent to the river and good picnic facilities.

Little Hendy redwood grove is a smaller though just as nice grove closer to the visitor center and is pretty much right above the banks of the Navarro River.   The primary trail is a single narrow oval loop with small elevation changes.  There are some large and unusual redwoods in Little Hendy Grove right along the loop.

Bridges cross small ravines (which can be wet in the winter) along Big Hendy Loop trail
A fine redwood near the Big Hendy Loop trail
Big Hendy loop trail
Little Hendy loop trail

Day Two – Humboldt Redwoods State Park Bull Creek Groves

I met John (the Eagles fan John) in the Tall – Giant tree area off Mattole Road.  We did some hiking in the flats on both sides of Bull Creek.  There were a few downed trees, especially on the north side of Bull Creek.  The Giant Tree dropped a big limb or two recently, smashing through the deck surrounding it and destroying the sign beside the deck.  There is also a big deep hole in the ground on the west side of the Giant Tree, obviously involving the Giant Tree’s roots.  It is worrisome. 

The drive along Mattole Road took me though the area where there was a big landslide last Spring.  About a quarter mile of the road is now gravel track, and there are many downed redwoods on the downhill side of Mattole Road through this area.

The Giant Tree deck and sign got whacked in the last year by large falling branches.
This redwood has been surrounded
Bull Creek north end trail a little east of the Tall Tree parking area. This redwood fell in the last year.

Day Three – Redwoods National Park Tall Trees Grove

I really enjoy the drive and hike to Tall Trees Grove, and the grove itself is great.  In the summer walking out onto the gravel bars of Redwood Creek from the Tall Trees trail is a must to see the giants in profile.  These redwoods are huge living things.

There was a lot of tree fall along upper Tall Trees grove trail last winter and many well executed repairs are visible on the upper part of the trail.  Down in the grove itself all the giants seem to be standing tall.  I spent a lot of time on the gravel bars taking in the views, both immediate and long distant.  The hike back up the steep hill is a good leg and lung stretcher and I enjoyed respites on a couple of well positioned benches.

These signs are up in the Tall Trees area. The Tom McDonald creek area is off limits, with severe penalties for entering the area.
The Tall Tree in Tall Trees Grove loop. Still a very tall redwood.
This big redwood on the Tall Trees loop fell five years ago – when upright it was called the Deadwood Giant.
Redwood Creek gravel bar looking south. Many tall redwoods both near and distant are in view.
A nice grouping of redwoods in the Talls Trees Grove. These trees are in the 100-100 club (over 100 meters height, over 100 Mg mass).

Day Four – Humboldt Redwoods Pepperwood Area, Smithe River State Natural Reserve, and Chamberlain Creek Waterfall Trail in Jackson State Forest Mendocino County

On day four I met Steve (the Cal Poly Humboldt Steve) and we did some hiking and work in the Pepperwood Area of Humboldt Redwoods State Park.   Most of the time we were in French Bell Grove, but we also went over to the north end of the Avenue to check out a few trees close to 101. 

Later that day I finally stopped at Smithe Redwoods State Natural Reserve along 101 north of Leggett.  Care needs to be taken exiting and entering 101 from the adjacent parking area as this is a high-speed curvy area of the highway.  Smithe Redwoods are on a nice flat above the Eel River and there is some impressive old growth there. A couple trees top out at 330 feet.

After this it was off to Chamberlain Creek Waterfall Trail between Willits and Fort Bragg in Jackson State Demonstration Forest in Mendocino County.  This area is a little remote and has gravel roads on the approach and it is good to have well researched written directions when driving there.  The trail is great, it starts from a road and moves sharply downhill into a creek valley filled with tall old growth redwoods.  The waterfall was flowing, and the wide cascade drops straight down a twelve foot or so wall of rock.  The waterfall and redwoods are in the same immediate area, so the vista is scenic and tranquil.

Big trunk and crown of large redwood in Grieg-French-Bell grove
Tallest redwood in the Pepperwood area, well over 350 feet and surrounded by poison ivy.
Some of the Smithe Redwoods are along 101 and can be approached from below. Avoid the road berm.
Steps leading down to Chamberlain Waterfall trail from gravel road
Tall old growth along Chamberlain Creek. Some trees are over 340 feet tall.
Chamberlain Creek Waterfall

Day Five – Henry Cowell Redwoods State Park and Aptos Creek in Santa Cruz County

The drive on day five was very interesting, taking expressways through the South Bay area and then the winding roads to the Felton – Henry Cowell Redwoods State Park – Roaring Camp area.  Henry Cowell Redwoods are beautiful, on a flat right above the San Lorenzo River.  There are many really big redwoods along the primary old growth trail.  This park has really nice facilities and a big parking lot near the trail entrance to handle a good number of visitors.

Later that afternoon I drove over to the Aptos Creek area to visit Ed (the Redwood Ed) and we took a nice walk and saw some big redwoods along Aptos Creek, very close to the Pacific Ocean.

Large redwoods along the loop trail in Henry Cowell redwoods
Large tree in Henry Cowell Redwoods, 280 feet tall and 1,500 years old
Redwoods along rail line in Roaring Camp area

I enjoyed my time in the redwood areas and meeting up with some good people. Thanks for reading.

Canopy Height Distribution in Old Growth Redwood Forests

Methods

This article is related to an earlier article posted on this web site, “Distribution of Tree Height in An Old Growth Redwood Forest”.   An analysis of recent LiDAR data allows for confirmation and expansion of the analysis in that article.

LiDAR data includes first return and ground points.  From this information height above ground can be calculated, typically at the square meter level using average ground elevation and maximum first return elevation within the square meter.  From this, derivative products can be created, including color height maps and data tables. 

In order to use the LiDAR data for canopy height distribution, I aggregated the results to 20 m x 20 m (400 square meter) tiles.  This is used to approximate crown spacing in old growth redwood forests.  The maximum calculated height above ground within each 400 square meter area is used to create the distribution graphs.  In practice the number of tiles is slightly greater than the number of actual redwood trees, by about twenty percent.  This is due to the same tree being included in two tiles.

Overall Results

Most importantly, redwood groves have a variety of footprints but similar distributions of tree height beyond the median height for the grove.  Some groves are thin wisps along canyon bottoms (think Big Sur) versus others are broad forests filling both sides of large valleys (think Prairie Creek).  But for most groves the very tallest trees in the grove are much higher than average height and the number of trees drops markedly in each ten foot height increment beyond the grove median height.

Redwood forests are amazingly scarce and small.  Coming out of the latest glacial maximum redwoods were few in number, then filled in a shifting northward range that represented just 2,000,000 acres in a 500 miles long by average six miles wide thin rectangle just inland of the Pacific Ocean from southern Oregon to Big Sur. In this range the needed blend of rare winter freezes (as redwoods cannot propagate by seed in areas with regular winter freezes) and regular intraday offshore to onshore summer fog (as fog hydrates the tall crowns of redwoods but lots of sun is also needed) occurs. Today’s remaining 100,000 or so old growth acres cover about the same range but in remnant patches, almost all in parks. 

Second, redwoods grow tall in good habitat throughout their range. Three-hundred-foot redwoods can be found from Big Sur to southern Oregon, and 328-foot (100 meter) redwoods can be found from the Santa Cruz Mountains to the Smith River near Crescent City.  Then the 50 or so tallest, those over 360 feet, can be found in Humboldt Redwoods State Park (about 33), Redwood National Park (about 13), and Montgomery Woods Reserve (about 4).  Prairie Creek Redwoods State Park and Jedediah Smith Redwoods State Park may also each have one or so 360-foot trees.

Third, old growth redwoods follow similar height distributions beyond a midpoint which is much lower than the maximum height in any particular grove.  The median height in a grove is typically 250-275 feet tall, with 300-foot redwoods often common and redwoods over 340 feet relatively rare.  When reviewed at the hectare level, the tallest canopies are around 340 feet median height.

The shortest trees reaching the canopy may be about 150 feet tall, there is no zero point.  This makes the distribution a truncated normal distribution, not a normal distribution. The canopy height distribution does follow a near normal distribution to the right of the canopy height midpoint.

Fourth, the tallest redwoods tend to clump together within groves. Reasons could be local light advantage, a local underground water source, common genetic specificity, or exceptional local soil conditions. The majority of the tallest redwoods have locally tall trees adjacent or nearby. The tallest redwoods tend to grow in groups of two, three, or four, with their tops twenty to thirty feet above the other tree tops in the same area. This is especially true on flats where the canopies are continuous rather than on slopes where the canopies tend to be emergent.

Demonstrated Canopy Height Distribution

The first area assessed are the Bull Creek and Eel River groves in Humboldt Redwoods State Park.

Here the canopy is relatively continuous within groves (in other words very few canopy gaps) with the exception of a couple areas.   This is a LiDAR color height map along Bull Creek in the Tall Tree area (Tall Tree / Rockefeller Redwood is in upper right).  The area shown covers about 500m x 500m.  Yellow is over 80 meters, orange over 90 meters, and red over 100 meters.  Here you can see yellows and oranges dominate, with most tree heights in the 275-300-foot range.  Then here and there are taller trees, which tend to clump together.

HRSP Tall Tree Area Color Height Map of Canopy (Tall Tree is to Upper Right)

This same pattern is repeated over and over in these groves, resulting in this aggregate canopy height distribution map:

Humboldt Redwoods State Park Old Growth Eel River and Bull Creek Canopy Height Distribution

To highlight what is shown, this is the percent of the canopy over given heights:

Over 280 feet    51%

Over 300 feet    35%

Over 320 feet    16%

Over 330 feet    8.5%      

Over 340 feet    3.5%                                

Over 350 feet    1.1%

Over 360 feet    0.2%    

Over 370 feet    0.01%

A top five percent tree is 340 feet tall. 

Then the second area assessed is a drainage well north of Humboldt Redwoods State Park.  Here the canopy is emergent, there are large gaps with lower heights but certainly many areas with tall redwoods, typically following slopes along and above creeks, which provide good soil and some wind protection.  This is a LiDAR color height map of a portion of the valley, covering about a 500m x 500m area. Yellow is over 80 meters, orange over 90 meters, and red over 100 meters.  Here you can see yellows and oranges in groups separated by lower canopy, with most tree heights in the 250-260-foot range.  Then here and there are taller trees. The tall trees are less dense, more spread out, versus Humboldt Redwoods State Park.

Northern redwood park Color Height Map of canopy in creek valley

A dozen similar areas were then aggregated to create this height distribution chart:

Area of Northern Redwood Park Canopy Height Distribution

To highlight what is shown, here is the percent of canopy above certain heights:

Over 260 feet    54%

Over 280 feet    25%

Over 300 feet      7%

Over 310 feet      3%

Over 320 feet    1.2%

Over 330 feet    0.3%      

Over 340 feet    .07%                                

Over 350 feet    .03%

A top five percent tree is 310 feet tall.

Putting HRSP and the northern redwood park area together in a graph of ten-foot height intervals above median height, it is evident both follow a similar distribution up to the tallest trees.  This is likely true when reviewing other old growth redwood areas. 

Height Distribution Ten Foot Intervals Right of Median

Finally this is a chart showing the canopy cross section in the three tallest 100m x 100m (hectares) in Humboldt Redwoods State Park. As noted earlier, the tallest trees tend to grow adjacently and are twenty to thirty feet above the average height in the local (one hectare) area.

Height Distribution HRSP Tallest Hectares

Redwoods became rare coming out of the latest ice age, then old growth redwoods became much, much rarer after commercial harvest.  Then within remaining old growth areas, the tree heights follow a truncated normal distribution, with decreasing numbers of trees for each ten foot increment above the local median. Then the tallest trees, those over 340 feet, are very uncommon and tend to clump together in very specific areas having the most optimal growing conditions.

Thanks for reading.