Greenheart

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Greenheart 2 X 4

Working: Easily sawn, in spite of a slight bunting effect. Turns well. Planning not difficult despite the high density of the wood and inter-locking grain.

A very heavy, hard timber, suitable for use under exacting conditions, outstanding in most of its strength properties, and of very high durability and having excellent resistance to attack from marine borers. Available in very large sizes and long lengths, and therefore suitable for pilings, piers, lock gates, docks and harbor works. Useful for pier decking and hand rails, flooring, and in the engineering industry as bearers for engines. Gives good service in chemical plants for vats, filter press plates and frames. Suitable for joinery in both exterior and interior situations, and used also for fishing rods and center laminar for long bows and general construction.           

Greenheart’s acid content is very low, calculated at 0.48% of acetic acid in air dried  wood, which represents a very low corrosive effect on nails, spikes and metal fasteners.

Greenheart marine decking

A constant factor in any marine installation involving the use of wood that it is subject to salt water action is that of deterioration due to the action of marine bores such as teredo and limnoria, and to decay due to the formation of wood forming fungi.  In this connection, it may be noted that the distribution and density of marine bores is constantly changing. A single teredo  may have as many as 500,000 offspring in one season,  reproduction starting when the teredo is only eight weeks old.  These marine bores are found in salt water all over the world, and they may change in numbers and localities over a period of years.  For example along the North American coast in 1939, 1940 and 1941 these increased 100 times as compared to their density several years previous. Five years later, by 1946, the limnoria were decreasing rapidly, but the teredo, which nearly disappeared in 1943, began to increase rapidly.

The most highly resistant wood to these two pests is Demerara or Greenheart, so named because of its greenish cast when split open.  It was first used as fenders on a dock in England over 150 years ago. It was the wood of the tree known as the Bebeeru, which only grows in British Guyana, South America, a country with an area of 83,000 square mile, approximately 60% of which is forest area.  Greenheart is more resistant to marine bores than any other species of timber tested by the U.S. Department of Agriculture for use as piling for piers, flooring, wharf’s, etc., and was also found to be highly resistant to wood destroying fungi in tests conducted over a long period of time by The U.S. Forest service, which also reported Greenheart surpasses iron and steel when used in water or contact with soil.

In forms of beams or posts, Greenheart has been found to be 25% stiffer than Black Locust, one of the strongest and stiffest of North American woods.  Likewise, Greenheart shows an elasticity in psi. of 3,500,000 as compared to Pine and 1,600,000 and 1,500,000 for Oak.  It is reported to have 80% the strength of steel.

The relative strength for construction purposes of Greenheart as compared to other woods is as follows: 

                            Greenheart   11.5

                            Oak                  5.0   

                            Teak                5.0

                            Pine                 5.0.

Greenheart is highly resistant to abrasion, which makes it particularly suitable for use in bulkheads, as sheathing for protection against floating ice, for flooring and decking, and for other similar marine applications. 

Among its mechanical properties, vouched for by The U.S. Forest Service tests, which are important when Greenheart is used as flooring, are a high bending strength 2.25 times that of White Oak and over twice that of Long Leaf Pine which makes an under floor unnecessary. 

Also Greenheart is twice as hard and over twice as stiff as White Oak, and has a greater ability to withstand shock.  Shrinkage is about 97% that of White Oak. As Greenheart has a low acid content, the corrosive effect on screws and, nails and bolts is at a minimum compared with other woods.

Greenheart is felled and then prepared in the form of round piling, ax-hewed squares and in various forms of sawn lumber and timber.  Greenheart piles can be driven as they are received, and after driving are cut off to grade by power saw.  When steam hammer is used they are not usually ringed.  However, if a drop hammer is used, it is recommended that they be ringed before driving, particularly if the driving is in hardpan, shale, and rock.  Greenheart has great strength, durability and load bearing capacity.

Greenheart does not require any treatment such as is usually the case with softer woods.  Its power of resistance to infection to its texture is due to the presence of an Amorphous Alkaloid, known as Bebeerins, from core to bark and resinous Tyloses.  This characteristic, besides making it resistant to marine bores, also make it highly fire resistant. 

Creosote treatments usually do not give protection to the entire wood as the usual penetration is only one to three inches, depending upon wood being treated, and abrasion or puncturing invalidates the protection, exposing the entire structure to decaying action or destruction by fire.

Examples of the resistance of Greenheart to damage and decay may be cited:

The Chesapeake & Ohio R.R. in 1936 drove Greenheart piles for their docks at Newport News and Norfolk, VA and for the car ferry slip at Norfolk.  Ten years later, in 1946 the piles were drawn out and re-driven, since they showed no signs of damage by marine bores or decay.  A shipyard on Long Island reports that Greenheart piles which seems to be impervious to the teredo attack all other piles lose their strength when treated for resistance to teredo and, as such have little or no value in installation where wearing surfaces and strength is required.

The fire resistance qualities of Greenheart were well demonstrated in a fire on a trestle of the Long Island R.R. at Rockway several years ago, a fire which destroyed several hundred feet of right of way.  “Ties treated with creosote burned fiercely and steel rails buckled from the heat. The supporting stringers were charred but the substructure of the trestle which was Greenheart remained in tact.”

In another case, when fire attacked the Pennsylvania Railroad Coal Dock at Greenville, NJ, the middle and outboard sections collapsed from intense heat, but the Greenheart sills and supporting posts on the approach trestle remained standing while the adjoining supports which were not Greenheart completely collapsed.  Similarly fire experiences elsewhere have attested to the effective fire-resistant qualities of Greenheart.

Marine bores are found along the Atlantic, Gulf and Pacific coasts and in fact in all salt waters.  Obviously, protection against the effects of their action is a matter of particular importance in those ports where traffic is heavy and wharf and dock facilities are in constant use   Probably, in terms of footage, the most extensive use of Greenheart is in the form of planking for warehouses and dock flooring, loading platforms, as fenders, ect.   Greenheart is also used extensively as piling for piers and docks, trestles, warehouse underpinning, coal pockets, bulkheads, dolphins, etc..   The need for high resistance to marine bores and wood destroying fungi being effectively fulfilled when Greenheart is used.

Savings in timber usage are illustrated in the following data relating to the requirements for a typical open top railroad dock with four tracks, where the first cost saving of amounts to 40%

With an annual cost savings of 60%.   A typical timber groin has shown saving of 37.5% in piles and 32.3% in timber.   Typical alternate uses of timber for piers and trestles were:

                                         GREENHEART            OTHER WOODS

Floor                                            2”                                       4”

Ties                                           4 x 8                                    8 x 8

Stringers                                  6 x 12                                  8 x 16

Braces                                      3 x 8                                    4 x 8

Sheet Piling                                2”                                         3”

Pile Clusters                     25 to 40% Less                                       

Pile Fenders                       11’ 3” centers                    7’  6” centers

Pile Bulkheads                     6” centers                           4” centers

Bulkhead Walling                    6 x 12                               12 x 12

Recent installation costs show the following comparative costs.   For a port tendered system, bids received for 1780 linear feet of abrasion piles 55’ 6” long shown in Greenheart as opposed to treated Pine, on 7’ 6” centers, showed no difference in cost.

When Delaware Lackawanna & Western Railroad Co. rebuilt its ferry rack in one of its slips in the Hudson River, 215 Greenheart piles, from 55 ft. to 70 ft. long, were used to replace 325 lumber piles.  In spite of the fact that the new rack was about 10 ft. longer than the one it replaced, the cost, when using Greenheart piling, was slightly less than the cost of the original piles in the shorter pier.

In a railroad transfer timber platform installation, a three inch under floor and a two inch wearing surface was laid down.  This was replaced by a two-inch Greenheart with no under-flooring, which gave ample strength and wearing surface without the sacrifice of any other essential qualities.  In this connection, it is interesting to note that while Greenheart at one time cost more than other hardwoods, under present conditions the costs are about the same.  This is due to the fact that while Greenheart has about doubled in price other hardwoods have increased three times or more.

In general, it may be stated that Greenheart, when used as piling exposed to marine bores, as flooring or decking, in ferry racks, driveways, or fenders, will give longer life, require much less frequent replacement, and will show high resistance to abrasion.  Greenheart can be worked as easily as other hardwoods and costs little, if anymore on a competitive installation basis, because fewer Greenheart piles are required in a given structure.  Amortization charges are less, due to the longer useful life of Greenheart.

See also:    

U.S. Department of Agriculture Handbook No. 207

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