தொல்தமிழர் அறிவியல் - 28
5. புல், மரம்
Only plants with woody parts are trees and shrubs.
Once you know that it has woody growth, you can determine whether it is a tree or a shrub. The generally acknowledged definition of a tree, according to USU, is a "woody plant having one erect perennial stem (trunk) at least three inches in diameter at a point 4-1/2 feet above the ground, a definitely formed crown of foliage, and a mature height of at least 13 feet."
Characteristics of Shrubs
Shrubs, therefore, are the opposite: a "woody plant with several perennial stems that may be erect or may lay close to the ground. It will usually have a height less than 13 feet and stems no more than about three inches in diameter." (The Spruce)
Difference between Tree and Plant
Trees and plants all fall under the same Plantae Kingdom, which is one of the five biggest Kingdoms that have been established to distinguish between the many living organisms that exist. The Plantae Kindom includes trees, shrubs, grass, herbs, bushes, vines, ferns, mosses, and even green algae. What makes them all common? Well, a few things.
First all plants are autotrophic eukaryotes, which means they cannot move from one place to another and they have the ability to create their own food. They also have a different cell structure that includes having rigid cell walls and is made up of cellulose. These features are shared by all of the members of the Plantae Kingdom.
Trees differ from other plants in the Kingdom because of their trunk, which earns them the name of a perennial plant. From the thick stem, more stems rise on which there are leaves. These leaves have the ability to trap energy from their sunlight and produce food using chlorophyll. The roots are well below the main trunk that are thick. Trees can grow for years in a habitable environment and do not die unless conditions prevent them from acquiring food and water. Many trees produce flowers and even fruits such as apples, mangos, banana, etc. -The Hindu.com
மேலும் சித்தர்கள் இயற்கையை ஆராய்ந்த முறை இன்றைய அறிவியலுக்கு முன்னோடி என்பதைக் கருத்தில் கொள்ளவும். பல் விழாத பாட்டி அன்று பல் தேய்த்த கரி, சாம்பல் வேப்பங்குச்சி , ஆலம் விழுது, செங்கா மாவு ஆகியன இன்று அறிவியல் ஆய்வுக்கூடத்தில் பற்பசை அவதாரம் எடுத்துள்ளன. இன்னும் சித்தர்கள் எழுதிவைத்த இஞ்சி, மஞ்சள், சுக்கு, மிளகு, திப்பிலி..தேன், இன்னபிற இலை , தழை, வேர், பட்டை யாவும் மருத்துவ அறிவியலுக்குச் சித்தர்கள் வழங்கிய கொடை என்பதை எவராலும் மறுக்க முடியாது.
“Tolkappiyam’s third division on societa matters of ancient Tamil land has a chapter on traditional classification of botanical lives. Trees that have solid and thick stem that develops into a trunk with even one metre in girth are discriminated from fragile grassy plants and herbs.
The surprising factor is that chapter in Tolkappiyam has a rich descriptive vocabulary for every stage of the growth of trees and plants.Vide: Marabiyal – Stanza No. 1586, 1587.” –Editor.----------தொடரும்……