Ohi'a 'Ohana

The Problem

The Ohi’a tree has a deep rooted significance to Hawaiian spirituality and native culture. The birth of children is often celebrated with the planting of a new Ohi’a tree along with umbilical cords, and the trees are considered sacred to locals. This tree is the most abundant native tree and its environmental importance for other organisms and the local ecosystem cannot be overstated. Today, the very existence of the Ohi’a tree is threatened by a Rapid Ohi’a Death (ROD), caused by a fungal pathogen which is new to science and for which no cure exists. The method of transmission is not yet known, but sawdust from beetle boring, open tree wounds, water or soil are suspected vectors. In an Earth Hacks marathon, we sought to find a way to identify ways to detect high risk disease areas and rapidly treat them on a large scale.

Our Proposal

Research papers from similar fungal parasites in sweet potatoes were used as supporting data for the conclusion that a pH of 5.5 creates favorable conditions for Ceratocystis fungus. Soil pH data and Ohi’a tree death data were used to develop a correlation between tree death and acidic soil conditions. From what we could find, pH data has not been published in the last 32 years. In order to confirm that pH is indeed a vector that affects Ohi’a susceptibility, low cost and small scale experiments should be conducted comparing trees exposed to infection in acidic soil as compared to neutral and basic soil. If it is found that pH is not a factor, it at the very least can be eliminated as a factor that affects proliferation as it has not yet been considered in current research. As part of our deployment strategy, we would like to leverage programs and “citizen science” tools such as Inaturalist, The Green Program, Bioblitz, and Kupu Hawaii to collect pH and soil data. These programs could also be used to implement strategies to reduce environmental stress on trees that makes them susceptible to infection. These strategies include providing crucial nutrients to the trees and amending soil pH to be less acidic. Cheap and easy-to-use pH testing strips could be utilized by citizens who can then submit the data online. We also believe that a low cost, harmless chemical such as calcium bicarbonate could be used to make the the soil more neutral without harming native vegetation.

We Assume that...

We are assuming that because the trees have such sacred meaning to the natives, we can utilize their help to compile a comprehensive data map of current pH levels throughout the island.

We are assuming that the pH strips would be simple and easy to use.

We are assuming that calcium bicarbonate could be a potential chemical to help normalize the conditions of the soil.

Constraints to Overcome

From what we could find, pH data has not been published in the last 32 years. This makes it difficult to predict current soil acidity and how it may affect this problem. Understanding the cultural value of these trees impacts how we look at providing solutions. Avenues regarding genetic engineering, introduction of invasive species or chemicals, and other unnatural methods would not be accepted in the Hawaiian community.

Current Work

We hope to slow the spread of the fungal pathogen, and, at best, eradicate it from the island of Hawaii by improving the soil conditions and update existing data of soil pH.

Current Needs

We need the help of scientists currently working on this issue to further understand its viability. If they agree that this is a feasible strategy, we could conduct small-scale experiments to see how much of a difference soil acidity is making.