You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCES TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     None. 
     REFERENCE TO A MICRO-FICHE APPENDIX 
     None. 
     TECHNICAL FIELD 
     This invention relates generally to wood flooring systems, and in particular, to an improved solid hybrid wood flooring product which combines the advantage of a thick wood wear layer similar to a traditional ¾ inch solid wood floor with the dimensional stability characteristics of engineered wood floor products, and which can be glued directly to concrete sub-flooring. 
     BACKGROUND OF THE INVENTION 
     The solid hybrid wood flooring system comprises a thick top layer of solid wood glued to a bottom layer of specially designed and modified solid wood. The top layer of an embodiment can be of any wood species and is approximately ¼ inch thick. This top layer thickness allows the end user to re-sand or re-finish the wood multiple times during the life of the wood floor, like solid wood flooring. The modified wood bottom layer comprises many small pieces of solid wood, glued together to make the layer. The grain of the wood comprising top layer and bottom layer are in parallel planar orientation, respectively. 
     When subjected to moisture, the top layer and each small piece of wood of the bottom layer will react and move in different directions, structurally pulling each other similar to the reaction of movements of the plywood layering of engineered wood floors, resulting in a dimensionally stable piece of solid wood flooring. The present invention can be installed by any traditional flooring methods, namely stapling, nailing, gluing, and floating. 
     The following Patents or Patent Publications are believed to be representative of the art: U.S. Pat. No. 6,162,312, issued Dec. 19, 2000; U.S. Patent Publication No. 2002/0152701, published Oct. 24, 2002; U.S. Pat. No. 6,878,228, issued Apr. 12, 2005; U.S. Pat. No. 5,736,227, issued Apr. 7, 1998; U.S. Pat. No. 5,738,924, issued Apr. 14, 1998; U.S. Pat. No. 5,736,218, issued Apr. 7, 1998; U.S. Pat. No. 4,831,806, issued May 23, 1989; U.S. Pat. No. 5,040,582, issued Aug. 20, 1991; U.S. Pat. No. 5,543,193, issued Aug. 6, 1996; U.S. Pat. No. 5,109,898, issued May 5, 1992; U.S. Patent Publication No. 2005/0268571, published Dec. 8, 2005; U.S. Pat. No. 6,695,944, issued Feb. 24, 2004; U.S. Patent Publication No. 2004/0074190, published Apr. 22, 2004; U.S. Pat. No. Des. 355,494, issued Feb. 14, 1995; and UK Patent Application Ser. No. GB 2,212,761, published Feb. 8, 1989. 
     BRIEF SUMMARY OF THE INVENTION 
     Two types of wood flooring products generally are available in the domestic market,  FIGS. 1 and 2 . 
     In the representative cross-sectional view of solid wood flooring  2 ,  FIG. 1 , the flooring is made from a piece of solid wood material. The total thickness of a solid wood plank is typically ¾ inch, and the plank further consists of tongue  12  and groove  16  construction. The top layer or upper portion  3  of the solid wood plank  2  enables the end-user to re-sand or refinish the layer during the lifetime of the wood floor, and is typically ¼ inch thick. Solid wood flooring is generally installed by nail or staple to plywood sub-floors. Since hardwood flooring is very sensitive to moisture, gluing it down to concrete sub-floors is not recommended. 
     Various attempts have been made to increase the stability of the wood floors. The most popular of these variations is engineered wood flooring,  FIG. 2 . 
     In the representative cross-sectional view of engineered hardwood flooring  5 ,  FIG. 2 , the flooring has a thin solid wood top layer  6  glued to the top surface of a core layer  7 . The top layer  6  is typically 2 millimeters to 4 millimeters thick. The core layer  7  is typically ⅛ inch to k inch thick and consists of tongue  12  and groove  16  construction, and is usually made of plywood. Engineered wood flooring is typically about 9/16 inch thick, and is generally installed by nail, staple, glue or float to sub-floor surfaces. 
     The cross grain layer construction of the plywood in the core layer  7  gives engineered wood a certain level of dimensional stability; however, the quality and perceived value of engineered hardwood floors are less desirable than solid wood flooring, and long-term performance is unsatisfactory. Over time, normal wear and tear from use and any re-finishing can often damage the thin wood top layer  6 , exposing the non-flooring material in the core layer  7 . 
     American consumers have preferred and enjoyed using real solid hardwood floors for more than 100 years, but most modern home developers build homes on concrete slab base sub-flooring. Therefore, it would be highly desirable to have a flooring board or system comprising solid wood materials, and yet provide enough dimensional stability to be glued down on top of the concrete sub-flooring. Additionally, in order to make it more affordable so that more people can enjoy using it, the new wood floor board should cost less to manufacture while providing all the aesthetic features and performance characteristics of a solid hardwood floor. Further, the new flooring should allow the user to maintain it in a manner similar to traditional solid hardwood flooring. 
     It is, therefore, one object to provide a new and useful two-layer hardwood flooring system providing a thick hardwood wear layer capable of being glued directly to concrete sub-flooring surfaces. 
     A further object is to provide a hardwood flooring system with superior hydroscopic dimensional stability. 
     It is yet another object to provide a two-layer, solid hardwood flooring system that provides the durability and aesthetic performance characteristics of traditional hardwood flooring. 
     It is a further object to provide an improved flooring system that reinforces sustainable forest product harvest practices and other environmentally sound timber logging methods. 
     It is yet a further object to lower the production costs of real wood flooring products, allowing more versatility in hard wood flooring applications and availability to more consumers. 
     An improved hardwood flooring product and system is thus provided for direct adaptation to concrete sub-flooring. In its broad form, this improved flooring provides the quality, aesthetic and durability of a thick wear layer present in traditional solid hardwood flooring while also providing the dimensional stability of engineered wood flooring. 
     Related features, objects and advantages of the present invention will be apparent with reference to the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view of conventional solid wood flooring. 
         FIG. 2  is a cross-sectional view of conventional engineered wood flooring. 
         FIG. 3  is an isometric view of a wood floor plank constructed according to an embodiment of the present invention. 
         FIG. 4  is a top view of the plank of  FIG. 3 . 
         FIG. 4A  is a cross-sectional view of the plank of  FIG. 4  taken at “A-A.” 
         FIG. 4B  is a detail view of the plank of  FIG. 3  taken at B. 
         FIG. 5  is an exploded isometric view of the plank of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings, an embodiment provides an improved and novel fabricated wood-flooring product  8 ,  FIG. 3 . The wood-flooring product  8  can be attached to any sub-floor including, but not limited to, concrete, wood, plywood, or oriented strand board (“OSB”) by using traditional fasteners, such as nail, staple or glue. Each plank or board of wood-flooring product  8  is between 0.25 inch and 1 inch, and the preferred embodiment is 0.75 inch, in total thickness. The width of the plank or board of wood-flooring product  8  is from two inches to ten inches. The length of wood-flooring product  8  is generally from one foot to eight feet. The solid wood-flooring product  8  comprises a top layer  10  and a bottom layer  18 . The top layer  10  is attached to the bottom layer  18  using conventional methods, such as adhesives, in conjunction with pressure so that the top layer  10  and bottom layer  18  are prevented from delaminating or separating from each other. 
     The top layer  10  is formed from a conventional hardwood flooring material in order to provide the desired durability and aesthetic appearance. Depending on the preference of color and/or wood grain, any wood flooring material can be chosen for the top layer  10 . The top layer  10  has a thickness between two millimeters and eight millimeters. This thickness range allows the top layer  10  to be re-sanded or refinished approximately 2-6 times before it is completely sanded through. Thus, any scratches or similar surface damage to the top layer  10  can be readily repaired or resurfaced similarly to a conventional ¾ inch thick hardwood floorboard. 
       FIG. 4  illustrates a top view of the wood floor plank  8  showing the micro-bevel  13  around the entire perimeter of the top layer  10  of the wood floor plank  8 . The micro-bevel  13  is cut at a 45 degree angle, and about 0.5 millimeter in width and depth,  FIGS. 4A and 4B . 
     The top surface  11  of the top layer  10 ,  FIGS. 3 and 4 , is manufactured in several conventional styles, such as traditional smooth surface, wire-brushed or hand-scraped, and the surface  11  can be stained to different colors or unstained. Typically, five to nine coats of a non-toxic, ultraviolet cured urethane base finish, such as ceramic oxide and the like, are applied to the top surface  11 . This finish provides a durable wear protection to the top surface  11 . 
     The bottom layer  18 ,  FIGS. 3 and 4 , when glued to the top layer provides a tongue  23  and groove  25 . The bottom layer  18  further comprising a plurality of small pieces of solid wood strips  21  glued together in a finger-jointed formation. This construction allows use of lower grade timber sources, reduces production costs, and increases the dimensional stability. As seen in  FIG. 4A , these small strips  21  have a generally uniform square or rectangular cross-sections. Each strip  21  has a thickness ranging from a quarter inch to three-quarters inch, a width ranging from half an inch to two inches, and lengths ranging from four inches to thirty inches. Since the principal purpose of the bottom layer  18  is to support the top layer  10 , wood strips  21  have no visual impact requirements. As the wood strips  21  are not visible after installation, lower grade solid wood materials can be used to form the bottom layer  18 . These small wood strips  21  are arranged to have the same grain orientation and are parallel to each other in the same grain direction of the top layer  10 . 
     The finger-jointed construction,  FIGS. 3 and 5 , method  22  is applied in the cutting and gluing of the small wood strips  21  to form the bottom layer  18 . This method of cutting increases the adhesion surface area of each wood strip  21 , which increases the bonding strength of the wood strips  21  after adhesive is applied. Further, the interlocking physical configuration of the finger-jointed  22  wood strips  21  also tends to minimize their hydroscopic movement, and which affords added dimensional stability to the bottom layer  18 . 
     The bottom layer  18  of the wood floor plank  8 ,  FIGS. 4A and 5 , comprises a four sided tongue and grove construction to facilitate installation. A tongue  23  is formed along the entire length of one longitudinal side of the bottom layer  18 . A groove  25  is cut in the bottom layer  18  and the groove  25  extends along the entire length on the opposing longitudinal side of the bottom layer  18 . The groove  25  sized and shaped to receive a tongue  23  from another wood floor plank  8 . The floor plank  8  also features tongue and groove construction on the butt end of each plank  8  in order to assure the interlocking of wood floor planks  8  abutting one another. A tongue  26 ,  FIG. 3 , is formed along the entire length of one end of the bottom layer  18 . A groove  27 ,  FIG. 3 , is cut in the bottom layer  18  along the entire length on the opposing butt end and is sized and shaped to mate with a tongue  26  of another wood floor plank  8  during installation. The tongues  23  and  26  and grooves  25  and  27  are formed and cut, respectively, only in the bottom layer  18 . 
     The wood flooring plank  8  further comprises kerfs  28 A-E on the bottom surface  20  of the bottom layer  18 . The kerfs  28 A-E add dimensional flexibility to the plank  8 . There are typically five kerfs  28 A-E on the bottom surface  20  of the bottom layer  18 . One edge kerr  28 A is cut approximately one inch from one of the longitudinal sides of the bottom surface  20  of the bottom layer  18  for the entire length of the bottom surface  20 . Another edge kerf  28 E is cut approximately one inch from one of the opposing longitudinal sides of the bottom surface  20  of the bottom layer  18  for the entire length of the bottom surface  20 . The balance of central kerfs  28 B,  28 C, and  28 D are equally spaced between the two edge kerts,  28 A and  28 E. Each kerf  28 A-E has a width ranging from 3 millimeters to 6 millimeters and a depth ranging from 6 millimeters to 13 millimeters. The kerfs  28 A-E effectively reduce the physical strength of the solid wood floor plank  8 , and thus add flexibility by allowing the plank  8  to better conform to slight irregularities in sub-floor surfaces. 
     The wood flooring plank  8  bottom layer  18  includes a bevel  30 ,  FIGS. 4A and 4B . The bevel  30  is cut 1 millimeter back on both sides along the entire length of the wood flooring plank  8 , at the lower edge of the bottom layer  18  of the bottom surface  20 . The bevel  30  is used to create a space to accommodate hydroscopic expansion from the bottom layer  18 . 
     One clear coat of a non-toxic, ultra-violet cured urethane finish is applied to the entire bottom surface  20  of the bottom layer  18 . This coat provides additional moisture protection for the bottom layer  18 , which increases dimensional stability for the entire wood floor plank  8 . 
     As can be seen from the foregoing, the improved wood flooring product provides a dimensionally stable, thick hardwood wear layer which can be installed over any sub-floor surface, particularly concrete. 
     Due to increased dimensional stability, the improved wood flooring product can be manufactured in longer and wider boards, typically 7 feet long by 7 inches wide which can be glued directly to concrete slabs. The consumer finishing-out a home with a concrete slab foundation can use the same flooring product on any level of the home, since the first floor can be glued to concrete and the second and higher floors can be nailed to wood sub-flooring. Similarly, consumers finishing-out multi-level high-rise apartment and condominiums living spaces with concrete slab flooring throughout can enjoy quality wood floors on all levels of their home. The longer and wider boards of the improved wood product also allow for faster installation. 
     For the purposes of promoting an understanding of the principles of the improved flooring product and system, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the flooring product or system is thereby intended, such alterations and further modifications in the illustrated embodiments, and such further applications of the principles of the flooring product or system as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates. 
     It should be understood that the improved wood flooring product and system are not intended to be limited by the specifics of the above-described embodiments, but rather by the accompanying claims.

Summary:
An improved fabricated hardwood flooring product providing the advantage of a thick wood wear layer similar to a traditional ¾ inch solid wood floor with the dimensional stability characteristics of engineered wood floor products.