Wednesday, April 23, 2008
The vog's effect on Protea
Conditions of Volcanic Out Gassing (VOG) continue around the south side of Big Island. The worst, so far, for us in Ocean View was overnight and morning of the 15th and 16th. That morning the civil defense trucks came by with loudspeakers suggesting voluntary evacuation due to high sulfur dioxide levels. The "danger" was gone by 10am, when the wind blew it all back out to sea, but the damage to the Protea plants had been done. When we went out to pick flowers 24 hours later, we found a whole field of burnt plants.Sulfur Dioxide, when mixed with water, forms sulfuric acid. While we could treat and use the water, any rain now would be very acidic. However, the sulfur dioxide as a gas, when present in high quantities, is taken into the bodies of living plants and animals through standard respiration (breathing) where it meets water in the cells, again forming sulfuric acid, burning from the inside.
Kilauea volcano has been producing 8-10 times the normal background rate of sulfur dioxide daily. The vog consists of this sulfur dioxide, volcanic ash, and dust. We have better days, but mostly it is hazy now and we seldom can see the coastline. We are having a particularly bad day today.
The Protea plants are still alive. No plant seems to have actually died. However, on many plants, much of the actively respiring tissue has been killed, and another episode like last week could finish them off. Older leaves, at the base of a branch, were often spared, as well as the newest, soft growth (new tissue that may have not yet begun respiration.) This produces a plant that looks burnt in the middle, yet growing from the tips.)
There are differing levels of damage on different Proteaceae species, and cultivars within the species. Australian Proteaceae seem to have sustained the least damage, although we have seen some effects on Banksia Prionotes and Grandis seedlings. The King Protea, with the waxiest of leaves, seems to have faired well, as have most of the leucadendron varieties (Safari Sunset.) The mink and Queen Proteas, and a majority of the Hawaiian leucospermum (pincushion) varieties, have taken the worst damage, varying by parentage. Showing the worst damage amongst the Protea was Pink Mink (Protea neriifolia.) Our leucospermums (pincushions) took a lot of damage; many of which were flush with new growth at the end of their flowering season. Pincushion varieties with glabrum, cuneiforme, or conocarpodendron parentage seem to have the most tolerance though still took damage, while those with cordifolium, tottem or reflexum parentage look so bad, it makes me want to cry. Leucospermum lineare, patersonii, and vestitium varieties, which are also common in Hawaiian pincushion, showed moderate damage, relative to the others.
The pictures don't do the damage justice; when you visit the field, what gets you first is the smell of dead vegetation. Each leaf, on many of the plants, is 75-90% dead. Two effect have been hard on the leaves: the extra particulate matter in the air, often the density of talc, sucks the moisture out of the tissue, leaving the leaves scorched on the tips and edges as though a very hot day after a period of water stress, dried them; then secondly the sulfuric acid effect, that appears almost like a chemical burn on the leaf, at first, then the burned tissue desiccates. The non-transpirant parts of the plants, very new tissue, stems, and leaf buds, do not seem effected. The plants, disregarding the damage, look very healthy, in fact the undamaged tissue has actually grown remarkably since the incident, as though the plants now have extra energy even as we deny them water.We are also seeing damage to some pincushion flowers, and the bracts (the colorful parts that surround, and are often mistaken for, the flowers) of the mink and Queen Protea varieties. In the pincushion flowers we have seen whole flower heads of shrivelled pins. In the Protea the damage appears as a bronzing of the colorful bracts surrounding the flower head. On some varieties this is more destructive to the look of the flower than in others.
Next steps: wait, wait and more wait. Some of the growers on the hill met with the government people, of course this has never happened before, so they can only help us test some theories of what might help, should it ever happen in the future. We are trying a couple of chemicals, in standard, controlled, tests on several varieties along with the other growers, but we know that its not really a viable way to grow the flowers. Even if a chemical could prove useful, could it possibly be worth the cost of applying it. Instead, we will hopefully determine what Proteacea can tolerate the conditions supplied by the volcano. We haven't heard how the Macadamia trees are doing yet. They were also at the end of their flowering cycle. Macadamia is a Proteacae too, from Tasmania, but like the other Australian Proteacae, it may tolerate the bad air more than the South African Protea and Leucospermum. We will have to wait, at least a season, before we remove anything from the ground that doesn't just die. It is important that we determine if the plants can recover, and what the long term effects will be. link | posted by Reese at 10:43 AM
