Trouble after removal of Silk Oak (Grevillea Robusta)

[csnewton]

With all of the winter storms we have had this year (N. California), it became apparent (for safety's sake) that we remove the Silk Oak tree that was 9 feet from our house. After the tree was removed, my husband cleaned up the site. That night he developed a "poison-oak like" rash all up and down his legs. Upon further investigation, we discovered that Silk Oak tree wood, "contains an allergen that causes dermatitis for many people." So, now our question is, what can we do with the site, to make it safe for people to be around it again. I have read that they had this problem in Hawaii, but no solutions. The stump has been ground, and we had as many of the grindings as possible hauled away. Is it an oil in the wood that causes this? Any ideas? We have three young boys, and I would like to take care of this soon, so that I don't have to worry about them getting the same rash. (It is real bad) We also want to plant something more appropriate in the spot, but I am afraid to go digging in that dirt. Any suggestions would be helpful.

Thanks,

Shannon

 

[treeseer]

Sounds like your tree increased in risk after cutting it down! :bang: I used to work on Grevillea a lot in Florida; never saw one go down in a hurricane.

Re allergens, it sounds like you have removed most of them. Jut wear protective clothing (gloves, long sleeves etc) when you work in the area, until your replacement plants are established.

 

[pigwot]

Grevillea robusta
Australian Silky Oak

This species is now extensively employed as a shade and timber tree in Ceylon and elsewhere.

"The sap irritates the eyes of men who prune the tree",(Maiden 1913).

"The tree is used to line streets for shade purposes and in Los Angeles "Grevillea poisoning" is well known to telephone linemen and pruners", (May 1960).

"Some of the laboratory staff most directly involved in handling and testing of specimens of this wood were affected with skin and eye irritation. Others as directly involved in this work were not affected. The irritation developed after handling green wood or following exposure to sawdust or exuded sap. It was not observed as a result of handling the dry prepared specimens", (U.S. Forest Service Research Note 1964).

"A male, developed vesicobullous dermatitis of the skin of the neck, arms, trunk and genital area, two days after he sawed a limb off a specimen of this tree. Sawdust fell on his face, neck and down into his clothing. A patch test to the sawdust produced a. bullous response at 36 hours; tests in controls were not recorded", (May 1960).

"The major phenolic constituent of the wood is grevillol (5-n-tridecylresorcinol)", (Cannon et al. 1970).

"G. robusta, G. pyramidalis and Persoonia elliptica have been found to yield 5-n-alkyl and 5-n-alkenylresorcinols. The major constituent of the vesicant exudate on the seed pods of Grevillea pyramidalis has been identified as 5-pentadec-10-enylresorcinol and traces of the same substance have been shown to be present in the wood of G. robusta", (Ritchie et al. 1965, Occolowitz and Wright 1962, Ridley et al. 1968).

These compounds are chemically related to the sensitising compounds of Toxicodendron.

Those are the references I found in a quick search, but as far as treatment, and how persistent the sap is...I could not find much at all...

 

[Treeman14]

I would not recommend planting anything in the same area. Silk oak has allelopathic tendencies (similar to walnut or Australian pine) that would inhibit the growth of certain plants or trees. If this is a lawn area, refill the hole with soil and sod. If its in a bed, cover with soil and mulch.

There are very few silk oaks left in this area due to several cold winters as far back as 1983/84. I've worked with a few guys who were highly allergic to silk oak, much like poison ivy. It never bothered me, but I can't go near a sycamore tree.

 

[csnewton]

Sounds like your tree increased in risk after cutting it down! :bang: I used to work on Grevillea a lot in Florida; never saw one go down in a hurricane.

Re allergens, it sounds like you have removed most of them. Jut wear protective clothing (gloves, long sleeves etc) when you work in the area, until your replacement plants are established.

The tree was topped about 15 years ago by the previous owners, so we had large unstable branches falling on our house in the high winds. When I talked to some tree folks, everyone felt that the tree was not a good one to keep so close to a dwelling. Maybe the tree is getting its revenge.

-Shannon

 

[csnewton]

Grevillea robusta
Australian Silky Oak

This species is now extensively employed as a shade and timber tree in Ceylon and elsewhere.

"The sap irritates the eyes of men who prune the tree",(Maiden 1913).

"The tree is used to line streets for shade purposes and in Los Angeles "Grevillea poisoning" is well known to telephone linemen and pruners", (May 1960).

"Some of the laboratory staff most directly involved in handling and testing of specimens of this wood were affected with skin and eye irritation. Others as directly involved in this work were not affected. The irritation developed after handling green wood or following exposure to sawdust or exuded sap. It was not observed as a result of handling the dry prepared specimens", (U.S. Forest Service Research Note 1964).

"A male, developed vesicobullous dermatitis of the skin of the neck, arms, trunk and genital area, two days after he sawed a limb off a specimen of this tree. Sawdust fell on his face, neck and down into his clothing. A patch test to the sawdust produced a. bullous response at 36 hours; tests in controls were not recorded", (May 1960).

"The major phenolic constituent of the wood is grevillol (5-n-tridecylresorcinol)", (Cannon et al. 1970).

"G. robusta, G. pyramidalis and Persoonia elliptica have been found to yield 5-n-alkyl and 5-n-alkenylresorcinols. The major constituent of the vesicant exudate on the seed pods of Grevillea pyramidalis has been identified as 5-pentadec-10-enylresorcinol and traces of the same substance have been shown to be present in the wood of G. robusta", (Ritchie et al. 1965, Occolowitz and Wright 1962, Ridley et al. 1968).

These compounds are chemically related to the sensitising compounds of Toxicodendron.

Those are the references I found in a quick search, but as far as treatment, and how persistent the sap is...I could not find much at all...

Thanks for all the info. My husband will be mighty glad that it did not get in his EYES!! The rash on his legs is horrible enough!

-Shannon

 

[csnewton]

I would not recommend planting anything in the same area. Silk oak has allelopathic tendencies (similar to walnut or Australian pine) that would inhibit the growth of certain plants or trees. If this is a lawn area, refill the hole with soil and sod. If its in a bed, cover with soil and mulch.

There are very few silk oaks left in this area due to several cold winters as far back as 1983/84. I've worked with a few guys who were highly allergic to silk oak, much like poison ivy. It never bothered me, but I can't go near a sycamore tree.

So, it is in an area where we could make it into part of the lawn. Would the sod that we lay there survive with the remaining bits of ground-up stump that is in the dirt?

-Shannon

 

[kennertree]

Interesting. Any time i prune or remove a black walnut I get the saw dust on my face and i break out in hives. Sounds very similar to the silk oak.

 

[Treeman14]

So, it is in an area where we could make it into part of the lawn. Would the sod that we lay there survive with the remaining bits of ground-up stump that is in the dirt?

-Shannon

Remove as much of the stump grinding debris as possible, then put down some good topsoil and the new sod should be fine.

 

[csnewton]

Remove as much of the stump grinding debris as possible, then put down some good topsoil and the new sod should be fine.

Great, thanks!

-Shannon