What is Tree: Definition and 312 Discussions

In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only wood plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are some three trillion mature trees in the world.A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier. Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the branches divide into smaller branches and shoots. The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development.
Trees usually reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms, bananas, and bamboos also produce seeds, but tree ferns produce spores instead.
Trees play a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, and they play a role in many of the world's mythologies.

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  1. bo reddude

    What are the forces on a cell in a tree vs on the surface of a tree

    Hey everyone. Let's say you have a tall tree. say, 10 m tall. Take a cubic cell 1mm in dimensions. Suppose the cell is at 1 m high in the center of the trunk of the tree. What are the forces acting on the cell? let's say tree cell's mass is t grams. its weight is F= ma = t (9.8) = 9.8 t...
  2. F

    Engineering Decision Tree Regression: Avoiding Overfitting in Training Data

    The decision tree in the following curve is too fine details of the training data and learn from the noise, (overfitting). Ref: https://scikit-learn.org/stable/auto_examples/tree/plot_tree_regression.html#sphx-glr-auto-examples-tree-plot-tree-regression-py I tried to remove the overfitting...
  3. C

    I Number of edges in a tree digraph

    I know that if an undirected graph is a tree then its number of edges satisfies ## |E| = |V| - 1 ##. If a directed graph ( digraph ) is a tree, is the result also true? ( I can imagine just taking an undirected tree and making its edges directed but this is specious since it's a little bit more...
  4. C

    I How to Land a Tree Flat in 3/4 Rotation: Solving the Equations

    Can anyone tell me how to solve this problem? I have the stem of a tree that is X feet tall. It's just a cylinder as the top and all branches have been cut off. I want to cut off the top portion such that when it falls, it will do precisely a 3/4 rotation and land perfectly flat. What fraction...
  5. O

    Electrical Why Do Some Sections of My Pre-Lit Christmas Tree Not Light Up?

    I have a Christmas tree that's pre-lit. The basic setup is each section of the tree has power, and a strand of wire that comes out and wraps around the tree. That strand passes through a bunch of green plastic connector things, which appear to be a splitter of some sort - the strand goes in...
  6. pinball1970

    Chornobyl Dark coloured tree frogs

    "..melanin pigmentation has been proposed as a buffering mechanism against ionizing radiation. Our results suggest that exposure to high levels of ionizing radiation, likely at the time of the accident, may have been selected for darker coloration in Chornobyl tree frogs." Part of the...
  7. Melbourne Guy

    Are we predisposed to run along the line of a falling tree?

    We have trams in Melbourne, and this weekend I watched a pigeon on the tracks fly up and along the route as the tram came along, being hit by the windscreen (it survived, no worries). Yet it could of flown up and across and escaped because the tram was higher than it was wide. It prompted the...
  8. T

    Patterns in dendritic tree branches of neurons

    I am looking for a study/ressearch that my have been done concerning patterns found in the dendritic tree branching of Neurons.
  9. M

    MHB Burning time of Christmas Tree

    Hey! :giggle: The burning time of an electric candle is between $60$ and $80$ hours. It is considered to be continuously uniformly distributed over this period. A Christmas tree with $12$ candles (independent of the burning time), only lights up as long as all candles are working. Determine...
  10. M

    MHB Tree Diagram - Error at production

    Hey! 😊 One box contains ten production parts, four of which have a production error. Three parts are removed from the box one after the other without putting them back. We consider the following events : A : the first production part that is removed is OK B : the second production part that...
  11. M

    Feynman rules and the tree level cross section of two scalar fields

    Hi there. I'm trying to solve the problem mentioned above, the thing is I'm truly lost and I don't know how to start solving this problem. Sorry if I don't have a concrete attempt at a solution. How do I derive the Feynman rules for this Lagrangian? What I think happens is that in momentum...
  12. A

    MHB Shadow Lengths: Friend vs Tree

    At certain time of day, the shadow of your friend who is 5 ft tall measures 8 ft. At the same time, the shadow of a tree measures 28 ft. Draw a diagram to represent the situation. How tall is the tree?
  13. M

    Construction Homemade tripod tree stump/root puller design

    WHAT: I'm designing a simple tree stump puller. It consists of a tripod made of square (or round, if it's easier) steel tubing with a winch at the top. The cable from the winch drops down, attaches to the stump, then pulls the stump upward. DIMENSIONS: The top of the tripod, where the winch...
  14. D

    Java Tree Map always gets initialised but shouldn't, why is that?

    here is the portion of code [Code tags added by the Mentors] public void addPosition(String name, String skillNames) throws ApplicationException { Position ps=new Position (name); //creating object position if(listaPosizioni.get(name)==null) { //checking if position already present...
  15. xyz_1965

    MHB How Do Shadows and Sun Angles Relate to Tree Height?

    A tree casts a 23-foot shadow when the angle of elevation of the sun is 52 degrees. (A) Find the height of the tree. (B) Find the length of the shadow when the angle of elevation of the sun is 38 degrees.Part (A) Let h = height of tree tan(52°) = h/52 tan(52°)(23) = h 29.4386575404 = h...
  16. marciokoko

    Hanging a basketball wooden backboard on a palm tree

    I have this backboard made of wood (gift). The board itself has 2 vertical wooden 2x4. I need to hang it on a palm tree. I've checked the measurements and the palm tree has a good 20 inches side to side (diameter). I've had 3 different ideas and Id like to get a better one. 1. Drill 2x10"...
  17. A

    Comp Sci Creating Huffman Tree with Coding Frequency

    First, I get the string and I find the frequency of the every character. My struct is: typedef struct huffman_tree{ char c; int freq; //unsigned? struct huffman_tree *left; // 0 (left) struct huffman_tree *right; // 1 (right) }huffman_tree; I write this to create Huffman tree...
  18. E

    B Probably a silly question about tree diagrams

    Each node of a tree diagram corresponds to an event (i.e. a subset of the sample space), and the probability of the event at any node occurring equals the product of the probabilities along the path from the root to that node. So considering the following two tree diagrams, I would have...
  19. F

    Upper bound height and lower bound height of a 3-ary ordered tree

    how to find upper bound height and lower bound height of 3-ary ordered tree that have leaves of 101? ( the tree don't have to be complete tree, but have to be have 3 children) $$m^h \ge 101=3^h \ge 101$$ $$log \, m^h \ge 101=3^h \ge 101$$ $$h \ge 5$$ but how to know upper bound and lower...
  20. F

    I How Many Regular Ternary Ordered Trees with Height 3 Exist?

    Summary: I’m not too familiar with ordered tree. I’m solving excercise about tree but i’m not sure it is right or wrong How many regular ternary ordered tree with height 3 (ordered tree means children of each vertex are assigned a fixed ordering)? What is the smallest and biggest radius for...
  21. oldsaltysailor

    A 80 foot tree weighing 4000 pounds will soon fall on my cabin

    Homework Statement: I have a 80 foot tree weighing 4000 pounds ready to fall on my cabin. How thick of a cable or a nylon rope a do I need to stop it from hitting the cabin? Homework Equations: m=f/g I am 82 years old and can no longer do the math on this real problem I have due to a brain...
  22. Tom Hammer

    An apple falls from a tree, Does the moon move as a result?

    I am interested in the following thought experiment: an apple falls from a tree on Earth. Does the moon move (although slightly)? I can see an argument for it doing so—the center of mass of the Earth has moved slightly away from the moon, so the moon would feel a slightly smaller force and would...
  23. S

    With what speed does the tip of a 25 meter high tree hit the ground?

    Hi, I am still working on the same exams problems, the second last one is giving me a bit of a headache after I found this https://physics.stackexchange.com/questions/2372/how-long-would-it-take-for-an-upright-rigid-body-to-fall-to-the-ground which contradicts my solution. Can I assume that when...
  24. S

    I  Find Two Equal Length Paths in a Tree Graph

    In order to try and sovle this problem, my idea here was to use an extremal argument, with two equal length maximum paths on a tree. I said that no matter where the two graphs started, they'd end up having to cross paths since if there were two distinct paths with equal lengths the graph would...
  25. Z

    Calculate the time of an all-to-all broadcast for a balanced binary tree (BBT)

    Hi, I have provided a procedure for broadcast for BBT at the following link: https://cs.stackexchange.com/questions/106631/all-to-all-broadcast-on-a-balanced-binary-tree But I am not getting the correct time as asked in the question: Required Timing equation is: ##(t_s + t_w * m* p/2)logp##...
  26. L

    MHB How to Balance an Imbalanced Syntax Tree?

    The question asks you to balance a syntax tree. The first part is to describe the tree transformations needed to make it a complete tree. I've attached an example of the transformation. We will know its a compete tree if (heightOfShortestSubTree -heightOfTallestSubTree<=1). Normal...
  27. B

    Max KE of a squirrel jumping from the top of a tree

    Homework Statement 1. A squirrel jumps horizontally from the top of a 25 m tall tree with a speed of 8 m/s. What is the maximum kinetic energy of the squirrel during it`s entire trip down to the ground from the top of the tree? 2.If another squirrel of the same mass jumps straight upward from...
  28. B

    The squirrel jumps horizontally form the top of the 25m tall tree

    HI. I need help with my physics hw. I do not need the answers but need a general guidance on how to solve the problem. Would appreciate it alot!
  29. C

    I Mass counter term is a derivative at tree level?

    I've heard the statement that by computing just the leading-order (tree level) diagrams of a process and then computing the derivative of this result with respect to the mass should correspond to the evaluation of the mass counter term diagrams. Can someone explain why this statement is...
  30. E

    MHB Find the distance between points C and D if the height of the tree is 4m

    So the question is...From point C on the ground level, the angle of elevation to the top of a tree is 30 degrees. From point D, which is closer to the tree, the angle of elevation is measured to be 45 degrees. Find the distance between points C and D if the height of the tree is 4m. I know...
  31. Imager

    LaTeX Math Equation Christmas Tree and Graph

    I posted this link a couple years ago, but just in case you need to draw a Christmas Tree: https://tex.stackexchange.com/questions/39149/how-can-we-draw-a-christmas-tree-with-decorations-using-tikz There are a lot of interesting variations posted, maybe PF could have our own contest! Here's...
  32. Felipe Lincoln

    Python Is machine learning entirely based on decision tree?

    Are all the machine learning predictor algorithm based on decision tree? Even classifier and regressors?
  33. M

    MHB Calculate Area of Tree Structure (Wondering)

    Hey! :o A DIN A4 sheet is divided into thirds. A rectangle is the root of the tree, the other two rectangles are each divided into thirds again. Two rectangles form the branches - one to the left, one to the right - the others are again divided into thirds and so on. I want to calculate...
  34. J

    Calculating Image Distance Using a Christmas Tree Ball

    Homework Statement You look at yourself in a shiny Christmas tree ball, which has a diameter of 9.63 cm. If your face is 7.81 cm away from the shiny ball, calculate the image distance. Homework Equations ? Thinking I would use magnification = di/d0 di = 0.0781m d0 = 0.0963m The Attempt at a...
  35. Stephenk53

    Tree of Saturn or alternatives

    I wish to create a tree of saturn (crystal formation using lead acetate and zinc), however I have very little experience in chemistry and I know lead acetate is toxic but I do not know how toxic. I know how to make the tree but I want to know if I should or if there is a safer alternative that I...
  36. Fernando Calvario

    Riding a bicycle around a tree w/ constant acceleration

    Homework Statement African baobab trees can have circumferences of up to 43.0 m. Imagine riding a bicycle around a tree this size. If, starting from rest, you travel a distance of 162 m around the tree with a constant angular acceleration of 5.00 × 10–2 rad/s2, what will your final angular...
  37. Ventrella

    A Binary fractal tree with equidistant leaves on a circle

    Does there exist a binary fractal tree… (reference: http://ecademy.agnesscott.edu/~lriddle/ifs/pythagorean/symbinarytree.htm ) …whose leaves (endpoints) lie on a circle and are equidistant? Consider a binary fractal tree with branches decreasing in length by a scaling factor r (0 < r < 1) for...
  38. C

    What is the Mechanical Advantage of this lever? (for pulling tree stumps)

    I am interested in building a lever system for pulling up small tree stumps. I have seen this demonstrated on youtube videos. For example... However, I am more interested in calculating the various forces and mechanical advantage for such a system so I can figure out the best lever length...
  39. S

    MHB Binary Search Tree - Sort the same BSTree by name or by weight

    I've tackled a lot so far! I've created methods to delete, get the weight, and sort the tree by name. My goal is to have my switch criteria change how the tree is sorted, either by weight or by name. I haven't figured out how to implement it within my switchCriteria() method, so I've been...
  40. S

    MHB Java- CompareTo with Binary Search Tree

    I am having a hard time implementing comparing a given String name with the names of the Dog objects in my binary Search Tree. The problem comes from my containsRecursive() method. I need to use a String name to find if the name is already in my Binary Search Tree.Here's what I've tried...
  41. S

    Algorithm for computing the depths of all the nodes of tree

    Homework Statement Give an algorithm for computing the depths of all the nodes of a tree T, where n is the number of nodes of T. a) What is the complexity of your algorithm in terms of Big-O? b) What is the best possible complexity that you believe can be achieved when solving such problem...
  42. S

    Array-list implementation of tree problem

    Homework Statement a) Draw a single binary tree that gave the following traversals: Inorder: T N C K V A S M W Q B R L Postorder: T C N V S A W M B Q L R K b) Assume that the binary tree from the above part (a) of this question is stored in an array-list as a complete binary tree as discussed...
  43. F

    Projectile Motion Problem (Physics 12) -- Apple core thrown from a tree

    Homework Statement A child sitting in a tree throws his apple core from where he is perched (4.0m high) with a velocity of 5.0 m/s [35 degrees above horizontal], and it hits the ground right next to his friend. A) How long is it before the apple core hits the ground? B) How far from the base...
  44. DaveC426913

    Preserving a cherry tree in a sculpture

    @phinds : this is for you. (posting publicly, for those who might want to chime in) The time has come to bring down our poor cherry tree. It's been with us since we moved in, 25 years ago. It's finally left this mortal coil (trees can't shuffle). We'd like to keep a piece of it, and have it...
  45. L

    Ward-Takahashi identities at tree level in scalar QED

    Homework Statement Let \Gamma^\mu be the three-point vertex in scalar QED and \Gamma^{\mu\nu} be the four-point vertex. Use Feynman's rule at tree level and verify that the Ward-Takahashi identities are satisfied: q^\mu \Gamma_\mu(p_1,p_2)=e[D_F^{-1}(p_1)-D_F^{-1}(p_2)],\\...
  46. M

    I Neutrinos interact with photon in "level tree"?

    i found reading the possible interaction of neutrinos with photons to not "level tree", what's the meaning of level tree? and how is that posibble ?
  47. Vital

    Find the height of the tree - understanding the task

    Homework Statement Hello! Please, help me to understand the task - I seem to fail to understand what goes where, and hence cannot proceed to solving the exercise. Please, take a look at the task, and then my questions. The task is on using the law of sines. Before trying to solve it I need to...
  48. BillTre

    New Dog Breed Evolutionary Tree

    A new evolutionary tree of dog breeds has been produced based on DNA sequences from over 100 breeds. The basenji is closest to the root in this survey. These are interesting dogs that don't bark, but make lots of other noises. The tree is circular with the root (oldest part) in the center and...
  49. I

    Can Anyone Help Me Fix My 3D Space Filling Tree Algorithm?

    Hi all, I need an algorithm that fills a 3d lattice from any point, always expanding (no return allowed as in ref. http://msl.cs.illinois.edu/~lavalle/papers/KufLav09.pdf). The cells must be visited just once. My efforts are contained in the attached file. It works ***almost*** correct. Some...