Bukhari

Hadith Commentary:
➊
In one narration, the name of this tree is given as Tuba.
(Fath al-Bari: 6/392)
In another narration it is stated:
“If a well-prepared, swift horse were to gallop for a hundred years, it would still not be able to cross it.”
(‘Umdat al-Qari: 10/609)
In Surah al-Waqi‘ah, Allah the Exalted has said regarding the shade in Paradise:
“There, in Paradise, the shade of the trees will be spread far and wide.”
(al-Waqi‘ah: 56:30)

➋
From the aforementioned hadiths and verses, it is as clear as daylight that Paradise is the name of a tangible reality, and those who consider Paradise to be merely a matter of dreams and imagination are in grave error.
It is possible that for such people, Paradise may remain nothing more than an unattainable dream.
May Allah the Exalted protect us from such misgivings.

➌
Some individuals have interpreted “shade” to mean comfort and blessing, but taking the literal meaning rather than this interpretation is more correct, because it is not possible to compare the things of this world with those of Paradise.

Hadith Commentary:
This shade will not be that of the sun, rather it will be the shade of Allah's light. Some have said it will be the shade of Allah's Throne, because there will be no sun in Paradise.

Hadith Commentary:
In one narration it is stated:
“The best, finest, well-prepared, swiftest horse would not be able to traverse it in a hundred years.”
(Sahih Muslim, Al-Jannah wa Na‘imuha, Hadith: 7139(2828))

Once, when the mention of Sidrat al-Muntaha came before the Messenger of Allah (sallallahu alayhi wa sallam), he said:
“A rider could travel under the shade of its branches for a hundred years.”
...
Or he said:
...
“A hundred riders could fit within its shade.
Upon it will be golden moths, and its fruit will be like large jars.”
(Jami‘ al-Tirmidhi, Sifat al-Jannah, Hadith: 2541)

Benefits and Issues:
There will be no sunlight in Paradise, but the existence of trees is itself a blessing, which makes the scenery pleasant.
Each and every tree in Paradise will be so large, and the spread of its branches will be such, that in terms of this world, it will cover thousands of miles.
From this, one can also estimate the vastness of Paradise.

Explanation of the Hadith:
In the mentioned hadith, there is reference to a tree planted in Paradise such that if a person were to travel under its shade on a mount for one hundred (100) years, even then its shade would not come to an end.

Paradise pertains to the Hereafter; its system, its environment, and its laws are entirely different from those of our earthly world. Therefore, it is completely incorrect to compare the laws of that world to the laws of this world.

When someone denies this by saying, “How can there be such a large tree and such a long shade?”

In reality, this hadith is an explanation of that verse of the Noble Qur’an in which it is stated:
«وَظِلٍّ مَّمْدُودٍ» [الواقعة: 30]
“And there will be extended shade.”

And while describing the breadth of Paradise, it is stated:
«وَسَارِعُوا إِلَى مَغْفِرَةٍ مِنْ رَبِّكُمْ وَجَنَّةٍ عَرْضُهَا السَّمَاوَاتُ وَالْأَرْضُ أُعِدَّتْ لِلْمُتَّقِينَ» [آل عمران: 133]
“And hasten towards forgiveness from your Lord and towards a Paradise whose width is as the heavens and the earth, prepared for the God-fearing.”

And in another place it is stated:
«سَابِقُوا إِلَى مَغْفِرَةٍ مِنْ رَبِّكُمْ وَجَنَّةٍ عَرْضُهَا كَعَرْضِ السَّمَاءِ وَالْأَرْضِ» [الحديد: 21]
“Hasten towards forgiveness from your Lord and towards a Paradise whose expanse is like the expanse of the heavens and the earth.”

So, when the expanse of Paradise is as the heavens and the earth, then it is not far-fetched that there should be such a great tree in Paradise whose shade does not end even after riding a mount under it for one hundred (100) years.

This very hadith is present in Sahih al-Bukhari under number (3252), and at its end, these additional words are found, that the Messenger of Allah sallallahu alayhi wa sallam said:
«وَاقْرَؤُا إِنْ شِئْتُمْ وَظِلٍّ مَّمْدُودٍ» [الواقعه: 30]
“And if you wish, then recite... and there will be extended shade.”

From the context of the hadith, it is clear that the Messenger of Allah sallallahu alayhi wa sallam is, in fact, explaining this noble verse: “There will be extended shade.” He sallallahu alayhi wa sallam described its length, and this was his sallallahu alayhi wa sallam’s duty—to explain and clarify the Qur’an and to elucidate its ambiguities and generalities. As the statement of Allah, the Exalted, is:
«وَأَنْزَلْنَا إِلَيْكَ الذِّكْرَ لِتُبَيِّنَ لِلنَّاسِ» [النحل: 44]
“And We have revealed to you the Reminder (the Noble Qur’an) so that you may make clear to the people what has been sent down to them.”

It has become as clear as daylight that the Messenger of Allah sallallahu alayhi wa sallam is the explainer and interpreter of the Qur’an. Therefore, just as the Noble Qur’an is definitive in its authenticity, likewise the hadith of the Messenger—upon him be blessings and peace—is also definitive in its authenticity, and there remains no room for the rejection of hadith.

Benefit:
In this hadith, there is mention of a tree in Paradise such that if a rider were to travel under its shade for one hundred years, its shade would not come to an end. And this is only a single tree—Allah has prepared in Paradise blessings even greater than this. Regarding the blessings of this world, Allah the Exalted has said, "You cannot enumerate them," so how could a human being possibly enumerate the blessings of Paradise?

Benefit:
It is established from this hadith that there will be tall trees in Paradise.