I am publishing my letter to the Albany City Council about the City’s plans to destroy most of the eucalyptus forest on Albany Hill. I am publishing it in three segments because it is long. The first segment explained why it is not necessary to destroy the forest. The second segment explains the consequences of destroying the forest. The final segment will explain why it is unlikely that the forest can be replaced by native trees.
Conservation Sense and Nonsense
Albany Hill. Source: Google Earth
December 5, 2022
Albany City Council
1000 San Pablo Ave
Albany, CA 94706
Dear Albany City Council:
SEE Part I: Appealing to the City of Albany to save its eucalyptus forest. Part II continues:
The premature destruction of the eucalyptus forest will have many negative consequences:
- The loss of significant amounts of fog drop from the tall trees.
- The creation of tons of wood debris that will contribute to fire hazards
- The regrowth of the trees into unstable multi-stemmed trees with lower fire ladders
- The loss of habitat for overwintering monarch butterflies
Harold Gilliam in Weather of the San Francisco Bay Area informs us that tall non-native trees in the East Bay produce significant amounts of water by condensing fog drip: “Eucalyptus and pine groves planted there long ago intercept large amounts of fog and cause a rainlike deposit of moisture. The fog drip during the summer months has been measured at a surprising 10 inches, an amount nearly half as great as the total rainfall…” Average rainfall in the East Bay is 21 inches per year, so this fog precipitation adds nearly 50% to total precipitation.
One of the planning documents for the tree removal project on Albany Hill speculates that there is less fog than in the past in the San Francisco Bay Area. According to an article in the New York Times, many people disagree with that assumption.
By precipitating fog drip during the otherwise dry time of the year, tall non-native trees reduce fire danger during the fire season. Moisture on the forest floor helps to retard ignition and slow the spread of fire. This was observed recently on the west side of Albany Hill when an arsonist set the forest afire in June 2022: “The Albany Hill fire, which was initially estimated around three acres with a slow rate of spread…” The fire was quickly extinguished.
This is where the fire in June 2022 occurred on Pierce St. Note resprouts of the burned trees in November 2022. Conservation Sense and Nonsense
Fog drip from the eucalyptus overstory is also irrigating the forest understory of many native shrub species, predominantly toyon. Historical records of Albany Hill tell us toyon was not there before eucalyptus was planted. The top of the hill is the driest area because it does not benefit from run off compared to lower elevations of the hill. The side of the hill facing the southwest is drier than northeast face of the hill because it is exposed to more sun and wind. Historically, oaks grew only on the northeast side of the hill where they were sheltered from the wind and the soil was moister. One of many questions about the new plans for Albany Hill that should be asked and answered is how the existing native understory can survive without fog drip and the wind shelter of the tall trees.
The City of Albany’s application for a grant from the California Coastal Conservancy predicts this future for Albany Hill: “The project will create more fire-resilient and healthy ecosystems by allowing native plant communities to return after eucalyptus removal…” In fact, the opposite outcome seems more likely. Without the benefit of fog drop from the tall trees and shelter from the wind, the existing native understory is unlikely to survive. The existing native understory did not exist on Albany Hill prior to the planting of eucalyptus.
This map (see below) of tree removal plans for Albany Hill shows where approximately 400 trees will be removed at the top of the hill. (The number of each tree planned for removal is listed on this map, some in sequences such as 1-25, indicating that 25 trees will be removed between the arrows on the map.)
Source: Arborist Report, SBCA Tree Consulting
Returning to the question of fire hazards, what will happen to all that dead wood? We get a preview of the answer to that question because the City of Albany recently destroyed between 14 and 20 eucalyptus trees (reports on the number of destroyed trees vary). We can see what happened to some of the wood (see below):
Some of the destroyed trees are still lying on the ground (see below). This tree has already resprouted.
Multiply that flammable wood debris by 400 to get a picture of the amount of wood debris the proposed project on Albany Hill will create. The arborist’s report for the eucalyptus removal project makes this recommendation regarding wood debris: “Logs and chips to remain – Cut trees, chip brush and allow mulch and logs to remain on the slope.”
We had a recent experience with the wood debris created by similar projects when UC Berkeley destroyed all non-native trees within 100 feet of the north side of Claremont Ave in fall 2020. Huge piles of wood chips and logs were stacked along the road, which the grant application claimed would be disposed of by generating electricity in a biofuels plant. No such biofuels plant exists and there are no plans to build it. Here is a photo (see below) of one of the wood piles that remained along the road for about 9 months before being distributed elsewhere throughout the Berkeley hills:
Bay Nature recently explained why we are unable to dispose of wood debris from the many fuels management projects being done in California. If you ever wondered why there are piles of wood chips in your parks or why the roads in the hills are lined with logs, this article explains. There aren’t enough lumber mills in California to keep up with all the logs or biofuel plants to keep up with the wood chips. Most of the trees killed by bark beetles or by wildfire can’t be salvaged because of the shortage of mills. The wood debris is the fuel for the next wildfire. Turning living trees into dead wood debris does not reduce fire hazards.
In addition to reducing fire hazards, Albany’s new plans for the eucalyptus forest on Albany Hill are also intended to address safety concerns. Based on the assumption that the eucalyptus trees will soon die, Albany wishes to reduce public safety hazards by pre-emptively taking trees down before they fall down. As I’ve said before, the assumption that the trees will soon be dead is mistaken. Furthermore, Albany does not intend to use herbicides on the tree stumps to prevent resprouts, which guarantees that they will resprout, creating multi-stemmed trees that will be less stable than the trees are now.
According to the arborist’s report for Albany Hill, there is also a history of unstable trees that grew from resprouts of destroyed trees: “Stump sprouts – Sixty-nine (69) trees have developed as stump sprouts, or trees that have grown back from the stump after being cut down. Because the prior tree stump eventually rots, the new growth is not always well anchored.” The staff report to the City Council on May 13, 2021 about the project said, “Multi-trunk trees are weaker structurally and produce more fire-hazardous debris than single-trunk trees.”
Trees develop their defenses against the wind as they grow in a particular environment. When their tree neighbors are destroyed, they are suddenly subjected to more wind than they can withstand. The arborist employed by the City of Albany acknowledges the potential for increased risk of windthrow: “Stands of trees act together to resist wind forces. When trees are removed from a stand or grove, the wind forces on the remaining trees are increased. This can be a concern when trees, which are currently considered low risk, receive increased wind exposure due to adjacent tree removal.”
The unstable multi-stemmed trees that grow from resprouts will also be subjected to more wind without the protection of other trees that have been destroyed. The proposed plans for extensive tree removals will result in a more dangerous forest of resprouts that are vulnerable to windthrow.
Destroying 400 eucalyptus trees on Albany Hill would create an overwhelming commitment to control resprouts mechanically. It is a challenge that the City of Albany has not been able to meet in the past, as evidenced by recent resprouts and multi-stemmed trees from past resprouts. However, I don’t mean to imply that I prefer the use of herbicides to prevent resprouts. A new forest of young, unstable eucalyptus trees with lower fire ladders is better than a forest that has been poisoned and the understory with it. Herbicides are also harmful to monarch butterflies and other insects.
My last visit to the City park at the top of Albany Hill was on Sunday, November 20th, the weekend before Thanksgiving, which is the optimal time to see monarch butterflies in their winter roost. We saw many monarchs in the trees that are slated for destruction and as it got warmer in the early afternoon, we watched them flutter to nearby trees. There were many other park visitors. Some were frequent visitors who helped us find the biggest clusters. Other visitors were as excited as we were to find the monarchs for the first time. This is to say, the disappearance of monarchs on Albany Hill would be a disappointment to the visitors to the park.
Monarchs roosting in epicormic sprouts of eucalyptus on the top of Albany Hill, November 20, 2022. Conservation Sense and Nonsense
According to Stuart Weiss of Creekside Science, that’s where monarchs begin their visit to Albany Hill: “…monarchs begin the season on the ridgetop, likely attracted by high insolation [sunshine]. Following the first storms of the season accompanied by strong winds, they move down the SW slope when storm winds (generally southerly) are too strong. The structure of the forest in the Cluster zone consists of a series of openings surrounded by denser forest, allowing some insolation with adequate wind shelter. These cluster sites tend to have visible sky overhead with relatively few canopy openings toward the horizon and moderate exposure to the SW (which may be related to afternoon insolation.”
Stuart Weiss was also interviewed by Bay Nature about the monarch butterflies on Albany Hill: “Weiss wants to preserve the eucalyptuses—invasive non-natives that they are—for the butterflies’ sake. ‘The monarchs made their choice,’ says Weiss. ‘They go for the eucalyptus, so we have to honor that.’ The key to a cozy roost, according to Weiss, is a configuration of mature trees that provide just the right mix of sunshine and protection from wind and storms. Monarchs prefer to cluster along Albany Hill’s city-owned ridgetop early in the season. Later in winter, they cluster on the hill’s privately owned southwestern slope, and near the condos at the foot of the hill’s western flank. The fate of the trees and the butterflies roosting on that land is unclear.”
Eucalypts are the preferred trees for over-wintering monarchs in California according to an analytical study of 205 over-wintering sites: “Three types of trees were used most frequently by roosting monarchs: eucalyptus (75% of the habitats primarily Eucalyptus globulus), pine (20% of the habitats primarily Pinus radiata), and cypress (16% of the habitats Cupressus macrocarpa). Twelve other tree species were identified…with a combined prevalence of only 10%…habitats had smaller populations when the roosting tree type was a species other than eucalyptus, pine, or cypress.”(1) (Three different studies by different authors are the source of these data, therefore they don’t add up to 100%.) In other words, virtually all of the trees used by monarchs for their winter roost are not native to the San Francisco Bay Area.
The third and final segment of my letter to the Albany City Council will be published tomorrow. It will explain why the eucalyptus forest cannot be replaced by native trees. Thank you for your visit today.
- Dennis Frey and Andrew Schaffner, “Spatial and Temporal Pattern of Monarch Overwintering Abundance in Western North America,” in The Monarch Butterfly Biology and Conservation, Cornell University Press, 2004.