East of the Mississippi, CPW defaults to clear, dry Western Cedar.  West of the Mississippi, CPW defaults to clear, dry, Port Orford Cedar.  For those who will be applying a finish, we will provide samples with your order upon request.

Three requirement for 'joined' exterior assemblies.  By "Joined' we do not refer to such methodologies as the typical carpenter's stacked assemblies, where layers are mounted onto layers and secured with screws or nails or bolts.  We are referring to assemblies that are secured by the sequence and complexities of their joinery, such as the Shinto shrine in Ise, Japan, which was built in the 3rd century and stands in pristine condition today! Or the Horyuji temple, built in 607A.D. in Kyoto and standing today!  Or a wood stave church near Oslo, Norway, built in the 13th century.  These, and other examples, have survived because, for one, they are beyond the reach of tourists which can account for so much of the damage to aging wood structures, but also because of the conditions that have seen the wood in a stable environment with regards to moisture and dryness, and not susceptible to the infestation of bacteria, or fungus.  With these conditions, and the wood itself--the right wood--will last a very very long time
.
1) The proper wood selection
2) An air-dried moisture content of no more than 7-9%.
3)  Stable grain patterns.
4) Sustainable Harvest

There are only a handful of suitable woods with the inherent properties that are genetically resistant to exterior elements.  This does not include a plethora of options drawn from the rain forests in a process closer to annihilation than sustainable foresting. Nor Larch, Spruce, Cypress, or even Sugar Pine, all of which exhibit certain properties conducive to withstanding the elements but not all the properties, such as their dimensional stability and their workability to joining and millwork.  If we were concerned with only a wood's gift for withstanding harsh conditions, then Larch alone is worthy of a ransom's prize: For the pilers that have held up much of Venice, Italy for the past 600 years, or the millions of board feet as railroad cross-ties and the engineering marvels of all those magnificent trestles.

When we look to suitable species for exterior joinery, we must go beyond its mere resistance to the elements and consider: 1) It's dimensional stability (Is the trunk straight and branchless and with good girth? 2) Does it expand and contract excessively? 3) Is it workable, as in can it be milled and shaped without splitting and checking and burning the cutting edges?

Teak, Cedar, Redwood, Mahogany, and Oak. 

Teak, Cedar, and Redwood are nearly identical in their resistant properties. Mahogany and Oak are far less resistant and require regularly maintained finishing seals.  All of the above will weather and gray out to an identical gray if either left unfinished or applied with a clear seal.  The difference is in their signature grain figuring, which once grayed, will be largely unrecognizable. Teak, Mahogany, and Oak possess a higher density, which means your gate will close with a little more authority, but not last any longer.  Of the cedars, Port Orford is about 2-1/2 times denser than the western reds, Spanish, and aromatic. 

Teak:  Plantation teak is largely harvested in Indonesia, but also in Central America. Mayanmar teak (formerly Burmese teak)) is theoretically prohibited because of it poor harvesting techniques, and yet is widely available through imports via China. It is important to insure teak purchases are certified, and to verify the certification. When advertised as 'cheap teak', you can be assured it is being illegally harvested in Mayanmar and sold via black market through China. Teak has excellent inherent tannins, or oils, resisting bacteria and fungus. Figured grain. Extremely workable wood.  
Retail Cost: approximately $30/per board foot.

Redwood:  Grown exclusively along a 200-mile stretch of northern California coastline.  Because this industry is so tightly regulated, the former logging giants of Humbolt and Mendocino counties are littered with abandoned mills.  It is currently being harvested on a short cycle, producing sustainable results that are, unfortunately, without the properties inherent in old growth harvests.  Redwood has a high concentration of tannins, like teak, that thwart the propagation of bacteria (rot).  These tannins require a growth cycle to mature into their full genetic strength and are consequently absent in the present-day harvests.  Due to the abnormally large diameter of the trunk, the 'heart grain', located near the center, and oldest part of the tree, is tight and stable.  But 'old'growth' redwood is available only as a recycled product, drawn largely from a series of former military bases in California that were built with old growth redwood and were all closed in the 90's.  The current 'short-cycle' redwood has a fibrosity in its grain that is far far more porous than old growth, and therefore, far less stable or visually pleasing. 
Retail Cost:  Approximately $7/per board ft. for kiln-dried clear all-heart. (In northern California.  Far far more elsewhere)

Mahogany: There are many species of mahogany--usually denoted by the country of origin, but not always. Santos, Sapele, African, Fiddleback, Philippine, Honduras, and Cuban. They are all exotic and endangered and yet with proper research, available as sustainable with the exception of Cuban.  The mahogany industry has been over harvested.  If a sustainable source can be found, look for full figuring and a deep reddish brown coloring.  Mahogany, although a good species for resisting the elements, does not posses the same ideal characteristics as teak, cedar, and redwood.  It will gray out if left natural.
Retail Cost: Approximately $7/per board foot.

Oak: There are approximately 600 species of oak.  Generally good strength and hardness and resistant to insect and fungi due to a high tannin content.  Red Oak is far preferable to White Oak.   The strongest and most stable red oaks are quartersawn.  What is quartersawn? Quarter-sawing gets its name from the fact that the log is first cut lengthwise into quarters, wedges with a right angle ending at approximately the center of the original. Each quarter is cut separately by tipping it up on its point and sawing boards successively along the axis. That results in boards with the annual rings mostly perpendicular to the faces. Quarter sawing yields boards with straight striped grain lines, greater stability than flatsawn wood, and a distinctive ray and fleck figure. 
Retail Cost: Approximately $3/per board ft.  Quartersawn: $7/Bd Ft.

Cedars:
Western Red: The more common cedar found in exterior constructions. Harvested in British Columbia, Canada in pockets of sustainability.  Certain related species harvested in the Pacific Northwest. Soft, porous fiber.  One of the more dimensionally stable woods.  One of the signature properties is the light and dark colorings, often within a single board.  Excellent resistance to insect and fungi. 
Retail Cost: Approximately $5/per board foot.

Port Orford: Grown and harvested and milled in small, select locations in the Pacific Northwest. 100% sustainable.  A creamy white hue, aging to a stately silvery gray.  Smooth with no raised grain. Due to the pale nature of its coloring, it gives unlimited options when staining.  (Redwood, teak, western cedar, and mahogany are dark and cannot take lighter stain pigments) A unique, strong ginger-like scent, due to a volatile tannin oils.  Approximately three times the density of western cedar.  Dimensionally stable.  Excellent resistance to insect and fungi infestation.  Although in some areas, the lower grade of Port Orford is available as a green, knotty product sold as decking, the clear, air-dried grade remains largely unavailable to the retail public.   This is the wood Charles and others used in the 1970's in San Francisco---until it was all gone.  A grove was planted in 1978, maturing in 2001, and once again, a return to a species favored above all others.

Port orford cedar has been used for Japanese Temples that still stand hundreds of years later.  In fact there are two examples of such temples, built in 607 A.D. and , as well as the Shamrock series of 100' racing sailboats designed and built for the America's Cup just prior to WW1.

Why doesn't CPW provide fence and gate posts? 
---------------1) Because we do not stock posts and are therefore subject to a similar over-the-counter cost as your local installer through his own preferred lumber yard.
--------------2) If we did stock posts-- in 6x6 and 4x4--there would be an added cost of crating and shipping to the site, resulting in a post per-foot cost that far exceeded what your installer paid locally.

  Why Port Orford cedar is not available nor milled to standard post dimensions.  Clear Port Orford Cedar is by all accounts unavailable over-the-counter, with a few exceptions in the Portland, OR area. Western Cedar is the most commonly used post preference.  East of the Mississippi, this is a special order item and you should allow two weeks.  For their CPW fence-lines, the vast majority of patrons opt for an STK grade.  This is a tight knotted grade.  For gate posts, the preference is often the clear grade.  A full discussion of post options, including the recommended technique for setting your posts is at the following link: <http://www.prowellwoodworks.com/gate/postholes.htm>

Matching a Western Cedar post to a Port Orford gate or fence panel.
---------------If allowed to weather, both gate and post will age within a season to the same weathered gray patina.
---------------If oiled (such as Sikkens), the posts and gate will be distinguished by their respective patinas. 
---------------If finished with a pigmented stain (such as Cabot's), the varying patinas of the post and gate can be blended by mixing stain pigments.  This is a rare approach, in that the vast majority of patrons allow the varying patinas to stand as an accent demarcating the panels and their workmanship, from the posts. 

Pressure-Treated Posts:
As discussed in the post link above, stay away from pressure-treated posts.  They may offer an affordable option to the cedar, but the damage incurred on a host of levels far exceeds your short-term savings. 

Requests:
"We'd like our CPW product in Ipe, please"
--------------- You'll have to shop elsewhere. 
"We'd like our CPW product in Teak, please"
--------------- Unlikely. 
"We'd like our CPW product in Mahogany, please"
--------------- Possibly. 
"We'd like our CPW product in Redwood, please"
--------------- Never. 

There are sounds reasons for the above restrictions.  Enough reasons to fill a book.  But reading books appears to be a lost pastime.  Writing books of this nature is left to pundits and alarmists and the dooms-dayers who are the watchdogs and activists no one listens to anyway.   

A WORD ABOUT WOOD MOISTURE CONTENT
Air-Dryng vs Kiln-drying and Exterior Joinery)

When wood is used as a construction material, whether as a structural support in a building or in woodworking objects, it will absorb or desorb moisture until it is in equilibrium with its surroundings. The equilibration process (usually drying) causes unequal shrinkage in the wood, and can cause damage to the wood if the equilibration process occurs too rapidly. The process of equilibration needs to be controlled in order to prevent damage to the wood.

If the wood moisture content is high during the point of construction, a joint will appear tight. It will remain tight as long as the moisture content in the wood remains unchanged.  But once the drying process begins, such as exposure to the dryer air and seasons, the wood will lose it's moisture and and its dimensional point will shrink, thus translating this tight joint into an unsightly gap.  Although the principles are the same for interior furnishings, they are exasperated dramatically with joinery that is fully exposed to the conditions and elements outdoors. 

So . . . working with dry wood in the shop is absolutely essential if the methods of construction are those of joined members and not the stacked, or layered, members of a typical carpenter's assembly.  And because of the relative importance of this feature, we are consequently overly concerned with the method of just how that wood goes from the green live fiber of a tree to the dry, stable fiber suitable for joinery.

Most all dried lumber sold across the counter in America is kiln-dried.  A quick reliable process that allows the turnover of inventory.
But the process itself is not dissimilar to a microwave.  The quick timeline can result in 'drying stresses' such as checks and cracks and a loss of inherent tanins in the wood. 
-- If capital outlay is involved (and it always is) air-drying means that this capital is stagnant for a longer time.
-- Drying by air, with the wood stacked and stickered to allow free air flow on all six sides, requires often valuable real estate at the mills be occupied for the slow process. 
--Purchasing a kiln, either electrical or solar, is expensive, but dramatically improves the turn-a-round of inventory from green tree to retail lumber yard.
But kiln-drying is a risky endeavor and can often result in defects that arise due to what's called the shrinkage anisotropy, which leads to warping: cupping, bowing, twisting, spring and diamonding. Essentially, the wood tissue is ruptured and the inherent fibers collapse and flatten above the saturation point.  In layman's terms, we are traumatizing the wood fiber, which was often only a few days or weeks before, a living tree in a forest.  We are evaporating the life-sustaining moisture, or 'greenness', in an accelerated timetable. 

Most air drying is performed as a stipulation by the end user.  A regular customer of a specific mill or sawyer, will require the stock be air-dried to better suit his purposes and provide the stability of the wood once acclimated to local conditions.  This customer (which by the nature of business almost never involves contractors and carpenters buying direct from their local lumber yard) may also request grain patterns, such as only vertical grain and quartersawn grain, to further the assurance of the most dependable stock. This is normally an option only available to those who purchase directly from a mill and in some quantities and with the regularity of a repeating customer.  The relationship between a woodworker and his sawyer is paramount to the quality of the end product.

Why bother?  Well, why bother putting a period at the end of this sentence  It requires almost no ink, and you will likely find the content of the sentence just as readable and legible without the period