UPDATE - Hakalau Forest’s 2021 Endowment Fundraising Campaign

Thanks to your generous support and donations during the last three months, we’re thrilled to report that we have reached 90% of our goal as you can see from our thermometer. Our campaign ends on December 31^st, so we need your help over the next three weeks to raise the balance, $12,862. Every donation, big or small, helps!

CLICK BELOW FOR MORE DETAILS IN OUR NEW 2021 BROCHURE 

SAVE THE DATE: Annual Meeting January 22nd at 10am including the election of new board members. More information in early January.

Aloha Friends of Hakalau Forest NWR!

As another year of the covid-19 pandemic comes to a close we have several noteworthy accomplishments to report on. Our bunkhouse facility renovation has been completed and several miles of fence replacement has occurred on the refuge. During the year we were faced with feral mouflon sheep breaching our upper Pua Akala boundary fence line. The animals were successfully dispatched and the refuge has initiated a contract to replace the upper boundary fence with 6’ ft. high sheep fence in 2022. A contract has already been let to complete the upper Pua Akala boundary and fence materials have been purchased for refuge staff and our watershed partners to begin upgrading remaining boundary fence in the coming year.

While the covid pandemic severely reduced the number of volunteer groups that the refuge was able to host in 2021, we did outplant nearly 3,000 common and endangered plants grown by Baron Horiuchi! Volunteer groups assisting in outplanting efforts included KUPU, the Boy Scouts, Mauna Kea Watershed Alliance, and the Big Island Invasive Species Committee. Many thanks for their kōkua!

That’s it for now. Wishing you all a safe and healthy holiday season!

Dr. Creighton M. Litton,

Dr. Christian P. Giardina,

Where is the carbon in Hawaiian montane wet forests? How will it respond to climate change in the form of rising temperatures? These are the types of questions that motivated us to initiate a research project in 2008 with funding from the National Science Foundation, the USDA Forest Service, and the College of Tropical Agriculture and Human Resources at UH Mānoa. Along with funding, we needed a small army of collaborators, research technicians, undergraduate students, graduate students and postdoctoral scientists to conduct this work. Luckily, it is not hard to recruit folks to work at Hakalau Forest National Wildlife Refuge and the adjacent Laupāhoehoe unit of the Hawaiʻi Experimental Tropical Forest! Almost 15 years later, we have gained some important insights on forest carbon cycling and how it will be impacted by rising temperatures, not only in Hawaiian forests but also in forests globally. We are happy to share some of these insights here with you. For details, see some of the many scientific publications that have been published on this work to date.

The most straightforward way to gain insight is to simply follow a given forest over time as temperatures gradually increase, but that would mean many decades of research to gain insight on questions that we need answers to today.

Studies over the past 30 years have relied on a variety of approaches, including: (a) experimental warming of forests, that is directly warming some part of a large forest or an entire (very small) forest by using buried cables underground and/or heating lamps aboveground; (b) using computer modelling and existing understanding of how temperature affects forest processes to make predictions about the future and (c) examining forests across natural temperature gradients; for example the change in temperature as you go north/south from the equator, or as you move up a mountain slope.

All of these approaches have utility, but they all also have drawbacks. (a) Warming is logistically difficult and expensive and can not be done on whole forests. (b) Modelling has increased in sophistication and utility but is only as good as the data being used to develop the model.

(c) Using natural temperature gradients to simulate temperature changes also has limitations. Processes in forest ecosystems are impacted by many driving forces besides temperature, such as what plant species make up the forest, how much rainfall an area receives, and what the soils consist of, all of which affects nutrient availability and forest productivity. In most places in the world, as you change elevation these factors other than temperature also change with elevation, which makes it very difficult to determine if observed patterns in forest processes are the result of changes in temperature or one of the other driving factors.

Our research used the natural temperature gradients with one important factor - Hawaiʻi has some very exceptional mountains due to lava flows. In Hawaiʻi, we were able to locate an elevation gradient on the Windward Hāmākua slope of Mauna Kea where only the temperature changes. Not only does species diversity stay constant with elevation along this gradient, but other important factors such as soil properties, water availability, and disturbance history also remain remarkably constant. Moreover, while the forests along our gradient are low in plant species diversity compared to other tropical forests globally, they are remarkably similar to other tropical forests globally in terms of size and number of trees, and how productive they are. So outside of differences in how many different and what kinds of trees are found in our forests in Hawaiʻi, our forests look and act like other tropical forests around the world. All of these factors make Hawaiian forests a great model study system.

As there are different approaches to quantifying temperature impacts on forests, there are also a lot of different approaches for quantifying forest carbon cycling. Carbon cycling, in general, refers to how much carbon exists in a given forest, where the carbon is found in that forest, and how much carbon flows into, within, and out of that forest. Because tropical forests can be very large, and carbon moves between all parts of a forest, you can imagine that modelling forests will be a fair bit easier that measuring them! But as we mentioned, even the best models require good data. An alternative approach for measuring carbon flows into and out of a forest is the eddy covariance or eddy flux method, where very precise instrumentation is organized along a tower that extends well above the forest canopy where the instruments can measure the forest ‘inhaling’ CO₂ during the day when plants take up CO₂ for photosynthesis, and ‘exhaling’ at night when photosynthesis has ceased but plants continue to respire. This approach provides a lot of data on what the forest is doing collectively, but does not provide much information on what part of the ecosystem is doing what. Finally, with a lot of hard work and openness to getting dirty you can measure all of the various components of a forest carbon budget, which is the approach that we have taken in this research.

You can think of a carbon budget like your bank account for simplicity. Your bank account has an overall total account balance, but also various subaccounts (e.g., checking, savings, college tuition, etc.) that contain funds that sum up to the total account balance. In addition, you constantly make transactions that move money into and out of the overall account and various subaccounts (i.e., deposits, withdrawals and transfers), thereby altering the overall account balance. Likewise, in a forest you have a carbon account balance, "carbon pools” can be viewed as the subaccounts. Taken together, these pools are referred to as forest carbon storage. Put another way, carbon storage is how much carbon exists in the whole forest, as well as how it is distributed across the various pools or compartments of that forest at a given point in time. Carbon fluxes (bank transactions in our analogy) are the flows of carbon into a forest (primarily via photosynthesis) and the movement of that carbon from one pool to another (subaccount transactions). This includes the loss of CO₂ back to the atmosphere via plant respiration – on a cellular level, plants respire more or less just as we or any other organism does.

Most carbon pools are estimated directly with sampling in the field (e.g., soil cores to estimate the amount of carbon contained as organic matter in soils), whereas carbon fluxes are estimated either directly or indirectly. For example, one carbon flux of great interest to us is how much carbon a forest sends belowground to support roots and symbionts (e.g., mycorrhizal fungi), which is referred to in the scientific literature as “total belowground carbon flux (TBCF)”. TBCF is remarkably difficult to estimate directly, if not impossible, but luckily there is an approach based on the law of conservation of mass – (matter can neither be created nor destroyed, but can be changed in form and/or moved around) – that allows an indirect estimate of TBCF that relies on directly quantifying all of the other inputs and outputs of carbon to the soil along with overall soil C storage, ultimately solving the equation for the one unknown, TBCF.

Of particular interest, we found that the highest live biomass carbon storage occurred in forests at MATs of 16-17°C, and a recent global model predicts a sweet-spot for carbon storage in live biomass in wet forests to occur at 16.5°C MAT. We take that as further indication that Hawaiian forests do act like other tropical forests, highlighting the value of this model study system for understanding both local/regional as well as global patterns.

Interestingly, the majority of the carbon pools measured, as well as overall ecosystem carbon storage, did not decrease or increase with warming temperatures. Only forest floor and log biomass declined with warming, but these were <10% of total ecosystem carbon storage. This is good news, in that it indicates that in the absence of changes in rainfall or disturbances like hurricanes or wildfires, increased temperature is not expected to adversely impact the ability of these forests to store large amounts of carbon – yet another service that these forests provide for the planet.

What about carbon fluxes, the other side of the carbon budget coin? As with carbon pools, we identified some of the highest carbon flux values that have been published in the scientific literature, a testament to how productive these forests are and solid evidence for why they should be conserved, not only for biodiversity but also for the carbon/climate benefits they provide.

We will concentrate here on the belowground component of the carbon budget because we are soil nerds and because soils contain the largest quantity of carbon in forests (globally, soils contain >3x as much carbon as the atmosphere, and ~4.5x times more carbon than all of the world’s living biota combined).

By building carbon budgets, however, we were able to look at this result in the context of the total carbon budget for these forests. Doing so revealed that the increased loss of carbon from soils via soil respiration was perfectly balanced by an increase in the flux of carbon to belowground by plants (the so called TBCF), with no change in soil carbon storage across this >5°C mean annual temperature gradient. Again, this is good news indicating that as long as only temperature is changing and there are no water limitations to growth or changes in disturbance regimes (e.g., hurricanes or wildfires), rising temperatures as a result of climate change will not reduce the capacity of tropical montane forests to store and sequester carbon. We like feel good carbon stories!

We would like to end by thanking you for having the patience to read this far, we sincerely hope that we did not ruin carbon for you. We would also like to thank all of the students, postdocs, technicians, collaborators, volunteers, administrators and funding agencies who have made this work possible. Mahalo nui loa for letting us to work and play in some of the most remarkable forests on the face of this planet.

In 1992, I was fortunate to get a permanent position with the Service at Hakalau Forest. As the Maintenance Worker Supervisor, my first marching order from Refuge Manager Dick Wass was to hire a small crew to conduct habitat management work. After rehabbing Nauhi cabin to use as a base of operations, five of us laid out a route for a fence unit below middle Honohina. We did the same for Unit 7, below the Shipman unit. The refuge contracted all fence construction so I helped with building the specs, and inspecting the work. Once a month the crew would conduct maintenance inspections of all the fenced units and repair any breaches. Often, we would find fallen ʻōhiʻa branches which would have to be cut with a chainsaw. I provided that in-house training.

One of the core tasks for the crew was feral ungulate control. We would trap, snare and hunt. With the help of a couple of volunteers, we built a kennel to house hunting dogs for the program. This was a very effective method, but unfortunately we had to shut down this program due a conflict with newly introduced Nene using the same habitat.

However, taking this position left a void in the organization at Hakalau Forest. The Regional Fire staff allowed me to assist by doing some of the same things I used to, like operating heavy equipment to maintain refuge roads and train others in contract management, especially in the area of fencing.

I've been blessed to have worked with great people, committed to the mission and with great work ethics. I've learned nothing gets done by itself and it's even better when a team, including support staff, gets to celebrate work done. After all, it's not only productivity that's important but spreading the word that natural resources are inherently valuable and deserve the protection of many people.

Aloha pumehana,

Andy Kikuta

The i’iwi is the iconic bird of the Hawaiian forest. And proudly upholding iconic status for the arthropod fauna of Hawaii is the happy-face spider. This endemic species belongs to the Theridion genus of spiders with almost 600 members worldwide, but the one most notably mentioned is our own, Theridion grallator. T. grallator was named in 1900 by a French naturalist, Eugene L. Simon, who is the most prolific spider taxonomist in history. The specimens for Simon’s work were collected by another great naturalist, R.C.L. Perkins, an Englishman who wrote Fauna Hawaiiensis. He is also remarkable for walking on lava barefoot.

With this sterling heritage, we must expect our happy-face spider to be special. And it is. First, the happy-face name. It comes from a pattern on its abdomen which often takes the shape of a smiling face. The colors can be red, yellow, white and black, but plain yellow is favored. Another feature of this spider is its long legs, which give rise to its scientific name, grallator, which means stilt-walker. Those legs come in handy at night when stalking for food. Their webs are very flimsy, not good for catching prey, so they rely on detecting vibrations transmitted by their prey through a leaf.

Besides its unusual human “face”, T. grallator also has behavior that we humans can relate to. Mothers guard their egg sacs and feed the spiderlings after they hatch. They will even adopt orphan spiderlings, not something we commonly associate with spiders.

Malama Aloha Fund, Fred Ramsey, James C. Shingle Family Fund

The Friends of Hakalau is a membership organization. Membership dues and donations to the Friends are our only source of funds allowing us to cover our expenses (for example this newsletter) and to make grants.