The results show that the allometry equation of tree height which has diameter at breast height as independent variable can better reflect the change of tree height in addition the prediction accuracy of the multivariate composite models is higher than that of the single variable models. These models were divided into two groups of single models and multivariate models according to the number of independent variables. We studied 53 fitted models, of which 7 were linear models and 46 were non-linear models. A total of 5503 Chinese Metasequoia trees were used in this study. The description of these rosaceous fruits shows that by the Middle Eocene several postulated "advanced" characters in Prunoideae were already present.Accurate tree height and diameter at breast height (dbh) are important input variables for growth and yield models. This lack of information in extant Prunus makes the recognition of species difficult at this time. However, only seven out of about 430 species of Prunus have been studied in detail. Variation in number of cell layers, and cell size and shape in each zone is similar to that seen in extant Prunus species. These three endocarps with enclosed seeds have a very similar anatomy. The inner integument consists of a single layer of rectangular, thin-walled cells, but the inner integument becomes multilayered in the micropylar region and along the vascular plexus. The outer integument in two seeds is composed of a single layer with alternating sclereids and thin-walled cells, while in the third seed only sclereids are present. Seeds are anatropous, bitegmic, and ventrally attached to the carpel, with a ventral raphe and a dorsal vascular plexus. Cells along the ventral suture are oriented parallel to the surface of the suture and have thin secondary walls and dark contents. Endocarps are sclerotic, with one or two ridges on the dorsal side, and a distinct ventral suture that is partially open toward the fruit apex where an obturator is present.
Fruits are ovoid, unicarpellate, single-seeded drupes. Three anatomically preserved endocarps, each with one enclosed seed, are described from the Princeton chert (Middle Eocene) Allenby Formation of British Columbia, Canada.
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